Equilibrium Small Circuit Double Covers of Near-Triangulations

近三角剖分图的均衡二重少圈覆盖(英文)

A near-triangulation is such a connected planar graph whose inner faces are all triangles but the outer face may be not. Let G be a near-triangulation of order n and C be an SCDC (small circuit double cover)[2] of G. Let Then, C0 is said to he an equilibrium SCDC of G. In this paper, we show that if G is an outer planar graph, δ(C0)≤2, otherwiseδ(C0) ≤4.

近三角剖分图是一连通平面图，其内面均为三角形而其外面可能不是．令Ｇ为一具有ｎ个节点的近三角剖分图，Ｃ为 Ｇ的一个小圈二重覆盖（ＳＣＤＣ）［２］．令则Ｃ０。称为Ｇ的均衡小圈二重覆盖．本文将证明：若Ｇ为外平面图，则 δ（Ｃ０）≤ ２；否则δ（Ｃ０）≤４。