ENGINEERING, VOL. 24, NO. 9, SEPTEMBER 2012 LEDGE AND DATA ENGINEERING, VOL. 24, NO. 9, SEPTEMBER 2012 Next, we will present the definition of distributed line graphs in an iterative manner, that is, we define the nodes and edges of Giþ1, the ðiþ1Þth graph of a series of distributed line graphs, by describing how to obtain Giþ1 from Gi, i ¼ 0; 1; 2; . . . Definition 1. Let the initial graph G0 ¼ ðV ; EÞ be a d-regular graph. A series of graphs Giþ1 ¼ DLðGi; vðiÞÞ with i ¼ 0; 1; 2; . . . , where node vðiÞ 2 V ðGi Þ satisfies 8u 2 ÀÀ Gi ðvðiÞÞ [ Àþ Gi ðvðiÞÞ; jvðiÞj juj; ð3aÞ is said to be a family of distributed line (DL) graphs with base d, if the following conditions hold: V ðGiþ1 Þ ¼ V ðGi Þ À fvðiÞg þ fu vðiÞju 2 ÀÀ Gi ðvðiÞÞg ð3bÞ EðGiþ1 Þ ¼ EðGi Þ À f½x; vðiÞjx 2 ÀÀ Gi ðvðiÞÞg À f½vðiÞ; yjy 2 Àþ Gi ðvðiÞÞg þ f½u; u vðiÞju 2 ÀÀ Gi ðvðiÞÞg þ f½u vðiÞ; wju 2 ÀÀ Gi ðvðiÞÞ;w 2 Àþ Gi ðvðiÞÞg: ð3cÞ The transition from Gi to Giþ1 is called distributed line iteration, and node vðiÞ is called responsible node. (We defer 1558 IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING, VOL. 24, NO. 9, SEPTEMBER 20 on of distributed line we define the nodes aph of a series of how to obtain Giþ1 ðV ; EÞ be a d-regular LðGi; vðiÞÞ with i ¼ 0; fies iÞj juj; ð3aÞ ne (DL) graphs with u 2 ÀÀ Gi ðvðiÞÞg ð3bÞ vðiÞÞg vðiÞju 2 ÀÀ Gi ðvðiÞÞg Gi ðvðiÞÞg: ð3cÞ led distributed line ible node. (We defer EE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING, VOL. 24, NO. 9, SEPTEMBER 2012 Next, we will present the definition of distributed line graphs in an iterative manner, that is, we define the nodes and edges of Giþ1, the ðiþ1Þth graph of a series of distributed line graphs, by describing how to obtain Giþ1 from Gi, i ¼ 0; 1; 2; . . . Definition 1. Let the initial graph G0 ¼ ðV ; EÞ be a d-regular graph. A series of graphs Giþ1 ¼ DLðGi; vðiÞÞ with i ¼ 0; 1; 2; . . . , where node vðiÞ 2 V ðGi Þ satisfies 8u 2 ÀÀ Gi ðvðiÞÞ [ Àþ Gi ðvðiÞÞ; jvðiÞj juj; ð3aÞ is said to be a family of distributed line (DL) graphs with base d, if the following conditions hold: V ðGiþ1 Þ ¼ V ðGi Þ À fvðiÞg þ fu vðiÞju 2 ÀÀ Gi ðvðiÞÞg ð3bÞ EðGiþ1 Þ ¼ EðGi Þ À f½x; vðiÞjx 2 ÀÀ Gi ðvðiÞÞg À f½vðiÞ; yjy 2 Àþ Gi ðvðiÞÞg þ f½u; u vðiÞju 2 ÀÀ Gi ðvðiÞÞg þ f½u vðiÞ; wju 2 ÀÀ Gi ðvðiÞÞ;w 2 Àþ Gi ðvðiÞÞg: ð3cÞ The transition from Gi to Giþ1 is called distributed line iteration, and node vðiÞ is called responsible node. (We defer the discussion on how to find vðiÞ to Section 4.1.) We say that the series of DL graphs is derived from initial graph G0. In Definition 1: (3a) puts restrictions on the responsible node of each DL iteration for balance purpose (which will be used in the following analysis in Section 2.5), i.e., the identifier length of vðiÞ is no greater than any of its direct neighbors; (3b) gives the new nodes generated by old edges; and (3c) presents the rules of generating new edges. Let’s take Figs. 2a, 2b, 2c, 2d, and 2e as an example to illustrate the decomposed procedure of DL iteration G1 ¼ 1558 IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING, V V(Gi+1 ) = V(Gi )∖{v(i)} ∪ {u ∘ v(i) ∣ u ∈ Γ− Gi (v(i))} E(Gi+1 ) = E(Gi )∖{⟨x, v(i)⟩ ∣ x ∈ Γ− Gi (v(i))}∖{⟨v(i), y⟩ ∣ y ∈ Γ+ Gi (v(i))} ∪ {⟨u, u ∘ v(i)⟩ ∣ u ∈ Γ− Gi (v(i))} ∪ {⟨u ∘ v(i), w⟩ ∣ u ∈ Γ− Gi (v(i)), w ∈ Γ+ Gi (v(i))} DK(2, 2) ͷ 1 Λબ͠ɺࢄϥΠϯάϥϑʹΑΓล-ભҠ ([6] ͷਤ 2. ΑΓ) d ݸͷ৽ͨͳ