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Millennium Prize Problems

Avatar for Luke Smallman Luke Smallman
November 16, 2016

Millennium Prize Problems

A two-part talk given at the SIAM PGR seminars at Cardiff University Maths department

Avatar for Luke Smallman

Luke Smallman

November 16, 2016
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  1. Structure Introduction P versus NP Riemann Hypothesis Navier-Stokes Existence and

    Smoothness Poincar´ e Conjecture Pause Hodge Conjecture Yang-Mills Existence and Mass Gap Birch and Swinnerton-Dyer Conjecture Finish 1
  2. Introduction • The Millennium Prize Problems were seven unsolved problems

    set out by the Clay Mathematics Institute • The Millenium Prize Problems are now six unsolved problems and one solved problem. 2
  3. Introduction • The Millennium Prize Problems were seven unsolved problems

    set out by the Clay Mathematics Institute • The Millenium Prize Problems are now six unsolved problems and one solved problem. • They have a certain level of infamy due to the Clay Mathematics Institute’s promise of $1 million for a correct proof of any of the problems 2
  4. The Deterministic Turing Machine Definition 2 The symbol denoting a

    blank Γ 2 A finite alphabet for the tape 4
  5. The Deterministic Turing Machine Definition 2 The symbol denoting a

    blank Γ 2 A finite alphabet for the tape Σ ⊆ Γ \ 2 The input alphabet 4
  6. The Deterministic Turing Machine Definition 2 The symbol denoting a

    blank Γ 2 A finite alphabet for the tape Σ ⊆ Γ \ 2 The input alphabet Q A finite, non-empty set of states 4
  7. The Deterministic Turing Machine Definition 2 The symbol denoting a

    blank Γ 2 A finite alphabet for the tape Σ ⊆ Γ \ 2 The input alphabet Q A finite, non-empty set of states F ⊆ Q The final or accepting states 4
  8. The Deterministic Turing Machine Definition 2 The symbol denoting a

    blank Γ 2 A finite alphabet for the tape Σ ⊆ Γ \ 2 The input alphabet Q A finite, non-empty set of states F ⊆ Q The final or accepting states q0 ∈ Q The initial state 4
  9. The Deterministic Turing Machine Definition 2 The symbol denoting a

    blank Γ 2 A finite alphabet for the tape Σ ⊆ Γ \ 2 The input alphabet Q A finite, non-empty set of states F ⊆ Q The final or accepting states q0 ∈ Q The initial state δ : Q \ F × Γ → Q × Γ × {L, R} The transition function 4
  10. The Deterministic Turing Machine Definition 2 The symbol denoting a

    blank Γ 2 A finite alphabet for the tape Σ ⊆ Γ \ 2 The input alphabet Q A finite, non-empty set of states F ⊆ Q The final or accepting states q0 ∈ Q The initial state δ : Q \ F × Γ → Q × Γ × {L, R} The transition function A DTM is then a 7-tuple M = Q, Γ, 2, Σ, δ, q0, F 4
  11. Complexity Class P Now we are ready to define P

    Definition A computational problem belongs to DTIME (f (n)) if it can be solved by a DTM in O(f (n)) computational time 5
  12. Complexity Class P Now we are ready to define P

    Definition A computational problem belongs to DTIME (f (n)) if it can be solved by a DTM in O(f (n)) computational time P = k∈N DTIME nk 5
  13. The Non-Deterministic Turing Machine Definition 2 The symbol denoting a

    blank Γ 2 A finite alphabet for the tape Σ ⊆ Γ \ 2 The input alphabet 6
  14. The Non-Deterministic Turing Machine Definition 2 The symbol denoting a

    blank Γ 2 A finite alphabet for the tape Σ ⊆ Γ \ 2 The input alphabet Q Finite, non-empty set of states 6
  15. The Non-Deterministic Turing Machine Definition 2 The symbol denoting a

    blank Γ 2 A finite alphabet for the tape Σ ⊆ Γ \ 2 The input alphabet Q Finite, non-empty set of states F ⊆ Q The final or accepting states 6
  16. The Non-Deterministic Turing Machine Definition 2 The symbol denoting a

    blank Γ 2 A finite alphabet for the tape Σ ⊆ Γ \ 2 The input alphabet Q Finite, non-empty set of states F ⊆ Q The final or accepting states q0 ∈ Q The initial state 6
  17. The Non-Deterministic Turing Machine Definition 2 The symbol denoting a

    blank Γ 2 A finite alphabet for the tape Σ ⊆ Γ \ 2 The input alphabet Q Finite, non-empty set of states F ⊆ Q The final or accepting states q0 ∈ Q The initial state δ ⊆ (Q \ F × Γ) × (Q × Γ × {L, R}) The transition relation 6
  18. The Non-Deterministic Turing Machine Definition 2 The symbol denoting a

    blank Γ 2 A finite alphabet for the tape Σ ⊆ Γ \ 2 The input alphabet Q Finite, non-empty set of states F ⊆ Q The final or accepting states q0 ∈ Q The initial state δ ⊆ (Q \ F × Γ) × (Q × Γ × {L, R}) The transition relation An NDTM is then a 7-tuple M = Q, Γ, 2, Σ, δ, q0, F 6
  19. Complexity Class NP Now we are ready to define NP

    Definition A computational problem belongs to NTIME (f (n)) if it can be solved by an NDTM in O(f (n)) computational time 7
  20. Complexity Class NP Now we are ready to define NP

    Definition A computational problem belongs to NTIME (f (n)) if it can be solved by an NDTM in O(f (n)) computational time NP = k∈N NTIME nk 7
  21. Riemann Zeta Function First definition ζ (s) = ∞ n=1

    1 ns s ∈ (1, ∞) 2.5 5.0 7.5 10.0 2.5 5.0 7.5 10.0 s ζ(s) ζ(s) for s > 1 9
  22. Riemann Zeta Function Second definition ζ (s) = ∞ n=1

    1 ns s ∈ C; R (s) > 1 Third Definition ζ(s) is the (unique) analytic continuation of the function in the second definition for all s = 1 10
  23. Zeros Trivial Zeros ζ(s) = 0 ∀ s ∈ {−2,

    −4, −6, . . .} Non-Trivial Zeros So far, every non-trivial zero of ζ(s) which has been found lies on the line 1 2 + it, t ∈ (−∞, ∞). 12
  24. Zeros Trivial Zeros ζ(s) = 0 ∀ s ∈ {−2,

    −4, −6, . . .} Non-Trivial Zeros So far, every non-trivial zero of ζ(s) which has been found lies on the line 1 2 + it, t ∈ (−∞, ∞). Highly Non-Trivial Zeros The statement of the problem is concerned with the existence of non-trivial zeros which do not lie on that line. 12
  25. Consequences of the Riemann Hypothesis Prime Number Theorem Using RH

    we get a tight bound on the remainder term of the prime number theorem expression for the number of primes below x π(x) = x 2 1 log t dt =:Li(x) +O( √ x log x) 13
  26. Consequences of the Riemann Hypothesis Prime Number Theorem Using RH

    we get a tight bound on the remainder term of the prime number theorem expression for the number of primes below x π(x) = x 2 1 log t dt =:Li(x) +O( √ x log x) In particular, RH implies |π(x) − Li(x)| < 1 8π √ x log x x ≥ 2657 13
  27. Consequences of the Riemann Hypothesis Growth of the Divisor Function

    Let σ(n) = d|n d. Then RH implies σ(n) < eγn log log n n > 5040 14
  28. Navier-Stokes Existence and Smoothness Problem Statement Prove that there exist

    smooth solutions with finite energy of the Navier-Stokes equations for any given divergence-free initial velocity field with no external force applied on either R3 or R3/Z. 15
  29. Navier-Stokes Existence and Smoothness Problem Statement Prove that there exist

    smooth solutions with finite energy of the Navier-Stokes equations for any given divergence-free initial velocity field with no external force applied on either R3 or R3/Z. OR prove that there exists a divergence-free intial velocity field and a smooth external force which does not have a smooth solution with finite energy. 15
  30. Navier-Stokes Equations Material Derivative We define D Dt := ∂

    ∂t + u · ∇ Incompressible Navier-Stokes Du Dt = −∇p + ν∇2u + F 16
  31. Navier-Stokes Equations Material Derivative We define D Dt := ∂

    ∂t + u · ∇ Incompressible Navier-Stokes Du Dt = −∇p + ν∇2u + F ∇ · u = 0 16
  32. Navier-Stokes Equations Material Derivative We define D Dt := ∂

    ∂t + u · ∇ Incompressible Navier-Stokes Du Dt = −∇p + ν∇2u + F ∇ · u = 0 Initial Conditions u(x, 0) = u0(x), u0 ∈ C∞, ∇ · u0 = 0 16
  33. Conditions Imposed Conditions Imposed on u0 and F We require:

    ∂α x u0 ≤ CαK (1 + |x|)−K ∀ K > 0, ∀ α ∈ N3 0 , ∀ x ∈ R3 17
  34. Conditions Imposed Conditions Imposed on u0 and F We require:

    ∂α x u0 ≤ CαK (1 + |x|)−K ∀ K > 0, ∀ α ∈ N3 0 , ∀ x ∈ R3 |∂α x ∂m t F| ≤ CαmK (1 + |x| + t)−K ∀ K > 0, ∀ α ∈ N3 0 , ∀ m ∈ N0, ∀ x ∈ R3, ∀ t ∈ [0, ∞) 17
  35. Conditions Imposed Conditions Imposed on u0 and F We require:

    ∂α x u0 ≤ CαK (1 + |x|)−K ∀ K > 0, ∀ α ∈ N3 0 , ∀ x ∈ R3 |∂α x ∂m t F| ≤ CαmK (1 + |x| + t)−K ∀ K > 0, ∀ α ∈ N3 0 , ∀ m ∈ N0, ∀ x ∈ R3, ∀ t ∈ [0, ∞) Physically Reasonable Solutions We require p, u ∈ C∞(R3 × [0, ∞)) 17
  36. Conditions Imposed Conditions Imposed on u0 and F We require:

    ∂α x u0 ≤ CαK (1 + |x|)−K ∀ K > 0, ∀ α ∈ N3 0 , ∀ x ∈ R3 |∂α x ∂m t F| ≤ CαmK (1 + |x| + t)−K ∀ K > 0, ∀ α ∈ N3 0 , ∀ m ∈ N0, ∀ x ∈ R3, ∀ t ∈ [0, ∞) Physically Reasonable Solutions We require p, u ∈ C∞(R3 × [0, ∞)) Rn |u(x, t)|2 dx < C ∀ t ∈ [0, ∞) 17
  37. Navier-Stokes Existence and Smoothness Problem Statement Prove that there exist

    smooth solutions with finite energy of the Navier-Stokes equations for any given divergence-free initial velocity field with no external force applied on either R3 or R3/Z. 18
  38. Navier-Stokes Existence and Smoothness Problem Statement Prove that there exist

    smooth solutions with finite energy of the Navier-Stokes equations for any given divergence-free initial velocity field with no external force applied on either R3 or R3/Z. OR prove that there exists a divergence-free intial velocity field and a smooth external force which does not have a smooth solution with finite energy. 18
  39. Poincar´ e Conjecture Problem Statement Prove that every simply connected,

    closed 3-manifold is homeomorphic to the 3-sphere. 19
  40. Manifolds Topology Given a set X, a topology τ on

    X is a collection of subsets of X such that • X ∈ τ, ∅ ∈ τ • The union of any collection of elements of τ is in τ • The intersection of any finite collection of elements of τ is in τ The elements of τ are then called open sets 20
  41. Manifolds Topology Given a set X, a topology τ on

    X is a collection of subsets of X such that • X ∈ τ, ∅ ∈ τ • The union of any collection of elements of τ is in τ • The intersection of any finite collection of elements of τ is in τ The elements of τ are then called open sets Topological Field A topological field is a field which is also endowed with a topology. 20
  42. Manifolds Topology Given a set X, a topology τ on

    X is a collection of subsets of X such that • X ∈ τ, ∅ ∈ τ • The union of any collection of elements of τ is in τ • The intersection of any finite collection of elements of τ is in τ The elements of τ are then called open sets Topological Field A topological field is a field which is also endowed with a topology. Topological Vector Space A topological vector space is a vector space X over a topological field K which is endowed with a topology such that vector addition and scalar multiplication are continuous functions. 20
  43. Manifolds Homeomorphism A homeomorphism is a continuous function between two

    topological spaces whose inverse is continuous. 21
  44. Manifolds Homeomorphism A homeomorphism is a continuous function between two

    topological spaces whose inverse is continuous. Manifolds A manifold M is a topological space which is locally homeomorphic to a topological vector space. 21
  45. Manifolds Homeomorphism A homeomorphism is a continuous function between two

    topological spaces whose inverse is continuous. Manifolds A manifold M is a topological space which is locally homeomorphic to a topological vector space. Compact Manifold A manifold M is compact if for every open cover there exists a finite subcover. That is ∀ {Ua}a∈A s.t a∈A Ua = M, Ua open ∃ J ⊂ A, | J |< ∞ : j∈J Uj = M 21
  46. Manifolds Closed Manifold A manifold is closed if it is

    compact and does not contain its boundary 22
  47. Manifolds Closed Manifold A manifold is closed if it is

    compact and does not contain its boundary Path Connected A manifold M is path connected if there exists a path connecting every two points in M 22
  48. Manifolds Closed Manifold A manifold is closed if it is

    compact and does not contain its boundary Path Connected A manifold M is path connected if there exists a path connecting every two points in M Simply Connected Formally, a manifold M is simply connected if it is path connected and any two paths from x ∈ M to y ∈ M are homotopic relative to their endpoints 22
  49. Manifolds Closed Manifold A manifold is closed if it is

    compact and does not contain its boundary Path Connected A manifold M is path connected if there exists a path connecting every two points in M Simply Connected Formally, a manifold M is simply connected if it is path connected and any two paths from x ∈ M to y ∈ M are homotopic relative to their endpoints 3-Manifold A 3-manifold is a manifold which is locally homeomorphic to R3 22
  50. Manifolds Closed Manifold A manifold is closed if it is

    compact and does not contain its boundary Path Connected A manifold M is path connected if there exists a path connecting every two points in M Simply Connected Formally, a manifold M is simply connected if it is path connected and any two paths from x ∈ M to y ∈ M are homotopic relative to their endpoints 3-Manifold A 3-manifold is a manifold which is locally homeomorphic to R3 3-Sphere S3 = x0, x1, x2, x3) ∈ R4 | x2 0 + x2 1 + x2 2 + x2 3 = 1 22
  51. Poincar´ e Conjecture Problem Statement Prove that every simply connected,

    closed 3-manifold is homeomorphic to the 3-sphere. 23
  52. Hodge Conjecture Problem Statement Prove that on a projective non-singular

    algebraic variety over C, any Hodge class is a rational linear combination of classes cl(Z) of algebraic cycles. 25
  53. Projective Algebraic Varieties over C Complex Projective Space The complex

    projective space of dimension n, denoted by CPn, is the set of all complex lines in Cn+1 which pass through the origin. 26
  54. Projective Algebraic Varieties over C Complex Projective Space The complex

    projective space of dimension n, denoted by CPn, is the set of all complex lines in Cn+1 which pass through the origin. Homogeneous Coordinates We can identify each line in a complex projective space with a set of homogeneous coordinates, usually denoted [z1 : z2 : · · · : zn+1]. These are unique up to scalar multiplication. 26
  55. Projective Algebraic Varieties over C Complex Projective Space The complex

    projective space of dimension n, denoted by CPn, is the set of all complex lines in Cn+1 which pass through the origin. Homogeneous Coordinates We can identify each line in a complex projective space with a set of homogeneous coordinates, usually denoted [z1 : z2 : · · · : zn+1]. These are unique up to scalar multiplication. Homogeneous Polynomial A homogeneous polynomial is a polynomial whose non-zero terms have the same degree. 26
  56. Projective Algebraic Varieties over C Complex Projective Space The complex

    projective space of dimension n, denoted by CPn, is the set of all complex lines in Cn+1 which pass through the origin. Homogeneous Coordinates We can identify each line in a complex projective space with a set of homogeneous coordinates, usually denoted [z1 : z2 : · · · : zn+1]. These are unique up to scalar multiplication. Homogeneous Polynomial A homogeneous polynomial is a polynomial whose non-zero terms have the same degree. Important property: if P(x) is homogeneous, then P(λ x) = λd P(x) 26
  57. Projective Algebraic Varieties over C Ring (R, +, ·) is

    a ring if: • (R, +) is an abelian group • · is associative in R • · has an identity in R • · is distributive over + 27
  58. Projective Algebraic Varieties over C Ring (R, +, ·) is

    a ring if: • (R, +) is an abelian group • · is associative in R • · has an identity in R • · is distributive over + Ideal Let (R, +, ·) be a ring. Then I ⊆ R is an ideal if: • (I, +) ≤ (R, +) • ∀ i ∈ I, ∀ r ∈ R, i ·r, r ·i ∈ I 27
  59. Projective Algebraic Varieties over C Ring (R, +, ·) is

    a ring if: • (R, +) is an abelian group • · is associative in R • · has an identity in R • · is distributive over + Ideal Let (R, +, ·) be a ring. Then I ⊆ R is an ideal if: • (I, +) ≤ (R, +) • ∀ i ∈ I, ∀ r ∈ R, i ·r, r ·i ∈ I Prime Ideal An ideal (P, +, ·) with P ⊂ R is a prime ideal if a, b ∈ R, a · b ∈ P ⇒ a ∈ P or b ∈ P 27
  60. Projective Algebraic Varieties over C Zero Locus The zero locus

    of a set of homogeneous polynomials S in CPn is defined to be Z(S) = {x ∈ CPn | f (x) = 0 ∀ f ∈ S} 28
  61. Projective Algebraic Varieties over C Zero Locus The zero locus

    of a set of homogeneous polynomials S in CPn is defined to be Z(S) = {x ∈ CPn | f (x) = 0 ∀ f ∈ S} Projective Algebraic Variety A projective algebraic variety is a zero locus of a set of homogeneous polynomials which form a prime ideal 28
  62. Singular Homology n-Simplex ∆n := (t0, . . . ,

    tn) ∈ Rn+1 | ti ≥ 0, n i=1 ti = 1 29
  63. Singular Homology n-Simplex ∆n := (t0, . . . ,

    tn) ∈ Rn+1 | ti ≥ 0, n i=1 ti = 1 Singular n-Simplex A singular n-simplex is a continuous map σn : ∆n → X, where X is a topological space 29
  64. Singular Homology n-Simplex ∆n := (t0, . . . ,

    tn) ∈ Rn+1 | ti ≥ 0, n i=1 ti = 1 Singular n-Simplex A singular n-simplex is a continuous map σn : ∆n → X, where X is a topological space Boundary Operator We denote the boundary of σn(∆n) by ∂nσn(∆n) 29
  65. Singular Homology n-Simplex ∆n := (t0, . . . ,

    tn) ∈ Rn+1 | ti ≥ 0, n i=1 ti = 1 Singular n-Simplex A singular n-simplex is a continuous map σn : ∆n → X, where X is a topological space Boundary Operator We denote the boundary of σn(∆n) by ∂nσn(∆n) Denote the group generated by the set of singular n-simplices by Cn(X). It is a free Abelian group. 29
  66. Singular Homology n-Simplex ∆n := (t0, . . . ,

    tn) ∈ Rn+1 | ti ≥ 0, n i=1 ti = 1 Singular n-Simplex A singular n-simplex is a continuous map σn : ∆n → X, where X is a topological space Boundary Operator We denote the boundary of σn(∆n) by ∂nσn(∆n) Denote the group generated by the set of singular n-simplices by Cn(X). It is a free Abelian group. We can extend the boundary to the boundary operator ∂n : Cn → Cn−1 29
  67. Singular Homology n-Simplex ∆n := (t0, . . . ,

    tn) ∈ Rn+1 | ti ≥ 0, n i=1 ti = 1 Singular n-Simplex A singular n-simplex is a continuous map σn : ∆n → X, where X is a topological space Boundary Operator We denote the boundary of σn(∆n) by ∂nσn(∆n) Denote the group generated by the set of singular n-simplices by Cn(X). It is a free Abelian group. We can extend the boundary to the boundary operator ∂n : Cn → Cn−1 It is a homomorphism 29
  68. Singular Homology Homology Group We define the ith homology group

    Ker(∂i )/Im(∂i+1) Its elements are known as homology classes. 30
  69. Singular Homology Homology Group We define the ith homology group

    Ker(∂i )/Im(∂i+1) Its elements are known as homology classes. Cohomology Group Consider the duals of Cn(X), denoted C∗ n (X) the corresponding dual homomorphisms dn : C∗ n (X) → C∗ n+1 (X) 30
  70. Singular Homology Homology Group We define the ith homology group

    Ker(∂i )/Im(∂i+1) Its elements are known as homology classes. Cohomology Group Consider the duals of Cn(X), denoted C∗ n (X) the corresponding dual homomorphisms dn : C∗ n (X) → C∗ n+1 (X) We now define the ith cohomology group Hi (X) := Ker(di )/Im(di−1) 30
  71. Hodge Class Hodge Decomposition A cohomology group Hi (X) can

    be decomposed (under certain conditions) as follows: Hi (X) = p+q=i Hp,q Where Hp,q is the subgroup of cohomology classes which are represented by harmonic forms of type (p, q) 31
  72. Hodge Class Hodge Decomposition A cohomology group Hi (X) can

    be decomposed (under certain conditions) as follows: Hi (X) = p+q=i Hp,q Where Hp,q is the subgroup of cohomology classes which are represented by harmonic forms of type (p, q) Hodge Class Hdgk(X) := H2k(X, Q) ∩ Hk,k(X) 31
  73. Algebraic Cycles Subvarities A subvariety Z of a variety X

    is a subset of X which is also a variety 32
  74. Algebraic Cycles Subvarities A subvariety Z of a variety X

    is a subset of X which is also a variety Algebraic Cycle An algebraic cycle on a variety X is a linear combination (with either integral of rational coefficients) of some set of subvarities Zi , of the form i ci Zi 32
  75. Algebraic Cycles Subvarities A subvariety Z of a variety X

    is a subset of X which is also a variety Algebraic Cycle An algebraic cycle on a variety X is a linear combination (with either integral of rational coefficients) of some set of subvarities Zi , of the form i ci Zi Cohomology Class of an Algebraic Cycle The cohomology class of the above algebraic cycle is i ci [Zi ] where [Zi ] is the cohomology class of Zi 32
  76. Hodge Conjecture Problem Statement Prove that on a projective non-singular

    algebraic variety over C, any Hodge class is a rational linear combination of classes cl(Z) of algebraic cycles. 33
  77. Yang-Mills Existence and Mass Gap Problem Statement Prove that for

    any compact simple gauge group G, a non-trivial quantum Yang-Mills theory exists on R4 and has a mass gap ∆ > 0. 34
  78. Yang-Mills Equations Yang-Mills Equations dDF = 0 ∗dD ∗ F

    = J Setting • We are working on a general manifold 36
  79. Yang-Mills Equations Yang-Mills Equations dDF = 0 ∗dD ∗ F

    = J Setting • We are working on a general manifold • For the standard model, it’s Minkowski space 36
  80. Manifolds and More Manifold A manifold M is a topological

    space which is locally homeomorphic to a topological vector space 37
  81. Manifolds and More Manifold A manifold M is a topological

    space which is locally homeomorphic to a topological vector space Tangent Space At each point p ∈ M we associate a tangent space TpM of all vectors tangent to p. If M is n-dimensional, then so is TpM for all p ∈ M. 37
  82. Manifolds and More Manifold A manifold M is a topological

    space which is locally homeomorphic to a topological vector space Tangent Space At each point p ∈ M we associate a tangent space TpM of all vectors tangent to p. If M is n-dimensional, then so is TpM for all p ∈ M. Vector Field on Manifold A vector field on a manifold is a map which associates p ∈ M to some v ∈ TpM 37
  83. Manifolds and More Manifold A manifold M is a topological

    space which is locally homeomorphic to a topological vector space Tangent Space At each point p ∈ M we associate a tangent space TpM of all vectors tangent to p. If M is n-dimensional, then so is TpM for all p ∈ M. Vector Field on Manifold A vector field on a manifold is a map which associates p ∈ M to some v ∈ TpM Commutator of Vector Field Given a vector-field X on M, we define X(p) to be the differential operator ∇vp 37
  84. Manifolds and More Manifold A manifold M is a topological

    space which is locally homeomorphic to a topological vector space Tangent Space At each point p ∈ M we associate a tangent space TpM of all vectors tangent to p. If M is n-dimensional, then so is TpM for all p ∈ M. Vector Field on Manifold A vector field on a manifold is a map which associates p ∈ M to some v ∈ TpM Commutator of Vector Field Given a vector-field X on M, we define X(p) to be the differential operator ∇vp Given vector-fields X, Y on M, we define [X, Y ] := X ◦ Y − Y ◦ X 37
  85. Manifolds and More Basis Vectors of TpM We denote the

    basis vectors of TpM by ∂i ≡ (0, . . . , 1, . . . , 0) 1 in the ith place 38
  86. Manifolds and More Basis Vectors of TpM We denote the

    basis vectors of TpM by ∂i ≡ (0, . . . , 1, . . . , 0) 1 in the ith place Cotangent Space Associate with each TpM the dual of that vector space, denoted T∗ p M which is the set of linear maps from TpM to R 38
  87. Manifolds and More Basis Vectors of TpM We denote the

    basis vectors of TpM by ∂i ≡ (0, . . . , 1, . . . , 0) 1 in the ith place Cotangent Space Associate with each TpM the dual of that vector space, denoted T∗ p M which is the set of linear maps from TpM to R Basis of Cotangent Space {dxj } j , dxj (∂k) := δjk 38
  88. Manifolds and More Basis Vectors of TpM We denote the

    basis vectors of TpM by ∂i ≡ (0, . . . , 1, . . . , 0) 1 in the ith place Cotangent Space Associate with each TpM the dual of that vector space, denoted T∗ p M which is the set of linear maps from TpM to R Basis of Cotangent Space {dxj } j , dxj (∂k) := δjk One-Forms A one-form ω associates each p ∈ M with an element of T∗ p M 38
  89. p-Forms Tensor Product For vectors v, w belong to a

    vector space V , v ⊗ w = wvT 39
  90. p-Forms Tensor Product For vectors v, w belong to a

    vector space V , v ⊗ w = wvT This can be generalised to arbitrary tensors (don’t ask) 39
  91. p-Forms Tensor Product For vectors v, w belong to a

    vector space V , v ⊗ w = wvT This can be generalised to arbitrary tensors (don’t ask) Wedge Product For vectors v1, v2 ∈ V , v1 ∧ v2 := v1 ⊗ v2 − v2 ⊗ v1 2 39
  92. p-Forms Tensor Product For vectors v, w belong to a

    vector space V , v ⊗ w = wvT This can be generalised to arbitrary tensors (don’t ask) Wedge Product For vectors v1, v2 ∈ V , v1 ∧ v2 := v1 ⊗ v2 − v2 ⊗ v1 2 For vectors v1, . . . , vn ∈ V , v1 ∧ · · · ∧ vn := π sgn(π)vπ(1) ⊗ · · · ⊗ vπ(n) n! where π are permutations. 39
  93. p-Forms pth exterior product For a vector space V ,

    the pth exterior product of V is Λp(V ) which is spanned by vectors of the form v1 ∧ · · · ∧ vp 40
  94. p-Forms pth exterior product For a vector space V ,

    the pth exterior product of V is Λp(V ) which is spanned by vectors of the form v1 ∧ · · · ∧ vp By convention, Λ0(V ) := R 40
  95. p-Forms pth exterior product For a vector space V ,

    the pth exterior product of V is Λp(V ) which is spanned by vectors of the form v1 ∧ · · · ∧ vp By convention, Λ0(V ) := R p-Forms A p-form is a map ω which associates to each p ∈ M an element of Λp(T∗ p M) 40
  96. p-Forms pth exterior product For a vector space V ,

    the pth exterior product of V is Λp(V ) which is spanned by vectors of the form v1 ∧ · · · ∧ vp By convention, Λ0(V ) := R p-Forms A p-form is a map ω which associates to each p ∈ M an element of Λp(T∗ p M) Ωp(M) denotes the set of all p-forms on M 40
  97. Exterior Derivative Exterior Derivative Rough Idea Usual definition of derivative

    lim h→0 f (x + hy) − f (x) h f (x + hy) lives in Tx+hy and f (x) in Tx 41
  98. Exterior Derivative Exterior Derivative Rough Idea Usual definition of derivative

    lim h→0 f (x + hy) − f (x) h f (x + hy) lives in Tx+hy and f (x) in Tx We can “identify” Tx+hy with Tx in some way and compute the derivative 41
  99. Exterior Derivative Exterior Derivative Rough Idea Usual definition of derivative

    lim h→0 f (x + hy) − f (x) h f (x + hy) lives in Tx+hy and f (x) in Tx We can “identify” Tx+hy with Tx in some way and compute the derivative Rules for Exterior Derivative Exterior derivative maps p-form ω ∈ Ωp(M) to (p + 1)-form dω ∈ Ωp+1(M) 41
  100. Exterior Derivative Exterior Derivative Rough Idea Usual definition of derivative

    lim h→0 f (x + hy) − f (x) h f (x + hy) lives in Tx+hy and f (x) in Tx We can “identify” Tx+hy with Tx in some way and compute the derivative Rules for Exterior Derivative Exterior derivative maps p-form ω ∈ Ωp(M) to (p + 1)-form dω ∈ Ωp+1(M) Exterior derivative is linear 41
  101. Exterior Derivative Exterior Derivative Rough Idea Usual definition of derivative

    lim h→0 f (x + hy) − f (x) h f (x + hy) lives in Tx+hy and f (x) in Tx We can “identify” Tx+hy with Tx in some way and compute the derivative Rules for Exterior Derivative Exterior derivative maps p-form ω ∈ Ωp(M) to (p + 1)-form dω ∈ Ωp+1(M) Exterior derivative is linear d(α ∧ β) = dα ∧ β + (−1)pα ∧ β 41
  102. Exterior Derivative Exterior Derivative Rough Idea Usual definition of derivative

    lim h→0 f (x + hy) − f (x) h f (x + hy) lives in Tx+hy and f (x) in Tx We can “identify” Tx+hy with Tx in some way and compute the derivative Rules for Exterior Derivative Exterior derivative maps p-form ω ∈ Ωp(M) to (p + 1)-form dω ∈ Ωp+1(M) Exterior derivative is linear d(α ∧ β) = dα ∧ β + (−1)pα ∧ β d(dω) = 0 41
  103. Exterior Derivative Exterior Derivative Rough Idea Usual definition of derivative

    lim h→0 f (x + hy) − f (x) h f (x + hy) lives in Tx+hy and f (x) in Tx We can “identify” Tx+hy with Tx in some way and compute the derivative Rules for Exterior Derivative Exterior derivative maps p-form ω ∈ Ωp(M) to (p + 1)-form dω ∈ Ωp+1(M) Exterior derivative is linear d(α ∧ β) = dα ∧ β + (−1)pα ∧ β d(dω) = 0 If f is a scalar field (i.e. a 0-form) then df = j (∂j f )dxj 41
  104. Exterior Derivative Exterior Derivative Rough Idea Usual definition of derivative

    lim h→0 f (x + hy) − f (x) h f (x + hy) lives in Tx+hy and f (x) in Tx We can “identify” Tx+hy with Tx in some way and compute the derivative Rules for Exterior Derivative Exterior derivative maps p-form ω ∈ Ωp(M) to (p + 1)-form dω ∈ Ωp+1(M) Exterior derivative is linear d(α ∧ β) = dα ∧ β + (−1)pα ∧ β d(dω) = 0 If f is a scalar field (i.e. a 0-form) then df = j (∂j f )dxj d(f ω) = df ∧ ω + fdω for all 0-form f 41
  105. Covariant Derivative or Connection Covariant Derivative Rough Idea Consider a

    notion of moving a tangent vector v at a point p in M to a tangent vector v at another point p in M, whilst keeping them the same. 42
  106. Covariant Derivative or Connection Covariant Derivative Rough Idea Consider a

    notion of moving a tangent vector v at a point p in M to a tangent vector v at another point p in M, whilst keeping them the same. j wj (∂j vk) = 0 42
  107. Covariant Derivative or Connection Covariant Derivative Rough Idea Consider a

    notion of moving a tangent vector v at a point p in M to a tangent vector v at another point p in M, whilst keeping them the same. j wj (∂j vk) = 0 This requires a local coordinate system, we want it to work in any 42
  108. Covariant Derivative or Connection Covariant Derivative Rough Idea Consider a

    notion of moving a tangent vector v at a point p in M to a tangent vector v at another point p in M, whilst keeping them the same. j wj (∂j vk) = 0 This requires a local coordinate system, we want it to work in any l wl (∂l v + Al v) = 0 42
  109. Covariant Derivative or Connection Covariant Derivative Rough Idea Consider a

    notion of moving a tangent vector v at a point p in M to a tangent vector v at another point p in M, whilst keeping them the same. j wj (∂j vk) = 0 This requires a local coordinate system, we want it to work in any l wl (∂l v + Al v) = 0 Define Dw v = l wl (∂l v + Al v) 42
  110. Vector Bundles Vector Bundle More generally, we can associate a

    vector space to each point in the manifold. Denote it Vp and we call it a fibre. M plus the Vps are called a vector bundle. (All fibres must have the same dimension) 43
  111. Vector Bundles Vector Bundle More generally, we can associate a

    vector space to each point in the manifold. Denote it Vp and we call it a fibre. M plus the Vps are called a vector bundle. (All fibres must have the same dimension) Sections A section is a map s which associates an element of Vp to each p ∈ M 43
  112. Vector Bundles Vector Bundle More generally, we can associate a

    vector space to each point in the manifold. Denote it Vp and we call it a fibre. M plus the Vps are called a vector bundle. (All fibres must have the same dimension) Sections A section is a map s which associates an element of Vp to each p ∈ M Covariant Derivative We can extend the covariant derivative to work on arbitrary sections in an analogous way 43
  113. Gauge Theory G-Bundle Given a group G and a representation

    of it V , define a bundle over a manifold M where each fibre is V . 44
  114. Gauge Theory G-Bundle Given a group G and a representation

    of it V , define a bundle over a manifold M where each fibre is V . Sections of a G-Bundle A section of this G-bundle assigns to each p ∈ M a group element g(p) acting on V . 44
  115. Gauge Theory G-Bundle Given a group G and a representation

    of it V , define a bundle over a manifold M where each fibre is V . Sections of a G-Bundle A section of this G-bundle assigns to each p ∈ M a group element g(p) acting on V . Gauge Symmetries and Groups We call g a gauge transformation or gauge symmetry and G the gauge group. 44
  116. Final Steps Curvature Given a covariant derivative, we define the

    curvature F(v, w)s := Dv Dw s − Dw Dv s − D[v,w] s 45
  117. Final Steps Curvature Given a covariant derivative, we define the

    curvature F(v, w)s := Dv Dw s − Dw Dv s − D[v,w] s Note that v, w are vector fields and s is a section. F(v, w) takes a section and returns another section. 45
  118. Final Steps Curvature Given a covariant derivative, we define the

    curvature F(v, w)s := Dv Dw s − Dw Dv s − D[v,w] s Note that v, w are vector fields and s is a section. F(v, w) takes a section and returns another section. Exterior Covariant Derivative Given a covariant derivative, you can define the exterior covariant derivative, in analogy to the exterior derivative. Denote it dD 45
  119. Final Steps Hodge ∗-Product Given a vector space V with

    orthonormal basis e1, . . . , en ∗(ej1 ∧ · · · ∧ ejp ) := sgn(j)ejp+1 ∧ · · · ∧ ejn 46
  120. Final Steps Hodge ∗-Product Given a vector space V with

    orthonormal basis e1, . . . , en ∗(ej1 ∧ · · · ∧ ejp ) := sgn(j)ejp+1 ∧ · · · ∧ ejn Extend this definition linearly to all of Λp(V ). 46
  121. Final Steps Hodge ∗-Product Given a vector space V with

    orthonormal basis e1, . . . , en ∗(ej1 ∧ · · · ∧ ejp ) := sgn(j)ejp+1 ∧ · · · ∧ ejn Extend this definition linearly to all of Λp(V ). This is then extended to any p-form ω ∈ Ωp(M). 46
  122. Final Steps Hodge ∗-Product Given a vector space V with

    orthonormal basis e1, . . . , en ∗(ej1 ∧ · · · ∧ ejp ) := sgn(j)ejp+1 ∧ · · · ∧ ejn Extend this definition linearly to all of Λp(V ). This is then extended to any p-form ω ∈ Ωp(M). Quantizing Once you’ve fixed a gauge group G and your connection (aka covariant derivative), you can construct a Yang-Mills theory 46
  123. Final Steps Hodge ∗-Product Given a vector space V with

    orthonormal basis e1, . . . , en ∗(ej1 ∧ · · · ∧ ejp ) := sgn(j)ejp+1 ∧ · · · ∧ ejn Extend this definition linearly to all of Λp(V ). This is then extended to any p-form ω ∈ Ωp(M). Quantizing Once you’ve fixed a gauge group G and your connection (aka covariant derivative), you can construct a Yang-Mills theory However, it still needs to be quantised, which is not necessarily easy. 46
  124. Yang-Mills Existence and Mass Gap Problem Statement Prove that for

    any compact simple gauge group G, a non-trivial quantum Yang-Mills theory exists on R4 and has a mass gap ∆ > 0. 48
  125. Birch and Swinnerton-Dyer Conjecture Problem Statement Prove that the Taylor

    expansion at s = 1 of the incomplete L-function L(C, s) of a non-singular projective model C of a curve C0 defined by f (x, y) = 0 for a polynomial f ∈ Q[x, y] has the form c(s − 1)r + higher order terms with r = rank(C(Q)). 49
  126. Curves Algebraic Curve An algebraic curve is a curve C0

    defined by the zeros of a polynomial in two variables p(x, y) 50
  127. Curves Algebraic Curve An algebraic curve is a curve C0

    defined by the zeros of a polynomial in two variables p(x, y) Plane Projective Curves Given an algebraic curve, we can define it’s corresponding plane projection C in the projective plane (RP2). ph(x, y, z) := zdeg(p)p( x z , y z ) 50
  128. Curves Algebraic Curve An algebraic curve is a curve C0

    defined by the zeros of a polynomial in two variables p(x, y) Plane Projective Curves Given an algebraic curve, we can define it’s corresponding plane projection C in the projective plane (RP2). ph(x, y, z) := zdeg(p)p( x z , y z ) Rational Solutions If p(x, y) ∈ Q [x, y], then we can look at the zeros in Q, denoted by C0(Q) (and correspondingly, zeros of ph in Q denoted by C(Q)) 50
  129. Characterising Curves Number of Solutions Either C0(Q) and C(Q) are

    finite, or they are both infinite Genus of Curves Plane projective curves C can be characterized by their genus , and we call the genus of C the genus of C0 too 51
  130. Characterising Curves Number of Solutions Either C0(Q) and C(Q) are

    finite, or they are both infinite Genus of Curves Plane projective curves C can be characterized by their genus , and we call the genus of C the genus of C0 too There are results about the size of C0(Q) for genus ≥ 2 and 0, but genus 1 remains open in general 51
  131. Group Structure Elliptic Curves If C is non-singular and has

    a rational point, then it is called an elliptic curve over Q 52
  132. Group Structure Elliptic Curves If C is non-singular and has

    a rational point, then it is called an elliptic curve over Q Mordell-Weil Theorem An elliptic curve C over Q defines a group C(Q) which satisfies C(Q) Zr ⊕ C(Q)tors 52
  133. Group Structure Elliptic Curves If C is non-singular and has

    a rational point, then it is called an elliptic curve over Q Mordell-Weil Theorem An elliptic curve C over Q defines a group C(Q) which satisfies C(Q) Zr ⊕ C(Q)tors We call r ∈ N0 the rank of C. C(Q)tors is some finite Abelian group. 52
  134. Group Structure Elliptic Curves If C is non-singular and has

    a rational point, then it is called an elliptic curve over Q Mordell-Weil Theorem An elliptic curve C over Q defines a group C(Q) which satisfies C(Q) Zr ⊕ C(Q)tors We call r ∈ N0 the rank of C. C(Q)tors is some finite Abelian group. r = 0 ⇔ |C(Q)| < ∞ 52
  135. Incomplete L-Series Necessaries An elliptic curve over Q can be

    written in the form y2 = x3 + ax + b 53
  136. Incomplete L-Series Necessaries An elliptic curve over Q can be

    written in the form y2 = x3 + ax + b ∆ := −16(4a3 + 27b2) 53
  137. Incomplete L-Series Necessaries An elliptic curve over Q can be

    written in the form y2 = x3 + ax + b ∆ := −16(4a3 + 27b2) Np := solutions of y2 = x3 + ax + b mod p 53
  138. Incomplete L-Series Necessaries An elliptic curve over Q can be

    written in the form y2 = x3 + ax + b ∆ := −16(4a3 + 27b2) Np := solutions of y2 = x3 + ax + b mod p ap := Np − p 53
  139. Incomplete L-Series Necessaries An elliptic curve over Q can be

    written in the form y2 = x3 + ax + b ∆ := −16(4a3 + 27b2) Np := solutions of y2 = x3 + ax + b mod p ap := Np − p Incomplete L-Series of C L(C, s) := p 2∆ 1 − app−s + p1−2s −1 For primes p. This converges for R (s) > 3/2 and can be continued analytically to the whole of C 53
  140. Birch and Swinnerton-Dyer Conjecture Problem Statement Prove that the Taylor

    expansion at s = 1 of L(C, s) has the form c(s − 1)r + higher order terms with c = 0 and r = rank(C(Q)) 54
  141. Birch and Swinnerton-Dyer Conjecture Problem Statement Prove that the Taylor

    expansion at s = 1 of L(C, s) has the form c(s − 1)r + higher order terms with c = 0 and r = rank(C(Q)) A Consequence L(C, 1) = 0 ⇔ C(Q) is infinite 54
  142. References and Links Problem Statements Problems statements sourced from the

    Clay Mathematics Institute This Presentation https://smllmn.com/talks 56