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On (s,t)-supereulerian graphs with linear degree bounds
Discrete Mathematics ( IF 0.7 ) Pub Date : 2021-03-01 , DOI: 10.1016/j.disc.2020.112239
Lan Lei , Wei Xiong , Yikang Xie , Mingquan Zhan , Hong-Jian Lai

Abstract For integers s ≥ 0 and t ≥ 0 , a graph G is ( s , t ) -supereulerian if for any disjoint edge sets X , Y ⊆ E ( G ) with | X | ≤ s and | Y | ≤ t , G has a spanning closed trail that contains X and avoids Y . Pulleyblank in [J. Graph Theory, 3 (1979) 309-310] showed that determining whether a graph is ( 0 , 0 ) -supereulerian, even when restricted to planar graphs, is NP-complete. Settling an open problem of Bauer, Catlin in [J. Graph Theory, 12 (1988) 29–45] showed that every simple graph G on n vertices with δ ( G ) ≥ n 5 − 1 , when n is sufficiently large, is ( 0 , 0 ) -supereulerian or is contractible to K 2 , 3 . We prove the following for any nonnegative integers s and t . (i) For any real numbers a and b with 0 a 1 , there exists a family of finitely many graphs F ( a , b ; s , t ) such that if G is a simple graph on n vertices with κ ′ ( G ) ≥ t + 2 and δ ( G ) ≥ a n + b , then either G is ( s , t ) -supereulerian, or G is contractible to a member in F ( a , b ; s , t ) . (ii) Let l K 2 denote the connected loopless graph with two vertices and l parallel edges. If G is a simple graph on n vertices with κ ′ ( G ) ≥ t + 2 and δ ( G ) ≥ n 2 − 1 , then when n is sufficiently large, either G is ( s , t ) -supereulerian, or for some integer j with t + 2 ≤ j ≤ s + t , G is contractible to a j K 2 .

中文翻译:

在具有线性度界的 (s,t)-超欧拉图上

Abstract 对于整数 s ≥ 0 和 t ≥ 0 ,如果对于任何不相交的边集 X , Y ⊆ E ( G ) 与 | ,则图 G 是 ( s , t ) -超欧拉图 X | ≤ s 和 | 是 | ≤ t ,G 有一条包含 X 并避开 Y 的跨越封闭路径。滑轮在 [J. Graph Theory, 3 (1979) 309-310] 表明,确定一个图是否是 ( 0 , 0 ) - 超欧拉,即使仅限于平面图,也是 NP-完全的。解决鲍尔、卡特林在 [J. Graph Theory, 12 (1988) 29–45] 表明,当 n 足够大时,n 个顶点上的每个简单图 G δ ( G ) ≥ n 5 − 1 ,是 ( 0 , 0 ) - 超欧拉或可收缩为 K 2、3。我们对任何非负整数 s 和 t 证明以下内容。(i) 对于任何具有 0 a 1 的实数 a 和 b,存在一族有限多图 F ( a , b ; s , t ) 使得如果 G 是 n 个顶点上的简单图,其中 κ ′ ( G ) ≥ t + 2 和 δ ( G ) ≥ an + b ,那么要么 G 是 ( s , t ) -超欧拉,要么 G 可收缩为F ( a , b ; s , t ) 中的成员。(ii) 令 l K 2 表示具有两个顶点和 l 条平行边的连通无环图。如果 G 是 n 个顶点上的简单图,其中 κ ′ ( G ) ≥ t + 2 和 δ ( G ) ≥ n 2 − 1 ,那么当 n 足够大时,要么 G 是 ( s , t ) -超欧拉,或者对于某个整数 j 与 t + 2 ≤ j ≤ s + t ,G 可收缩为 aj K 2 。
更新日期:2021-03-01
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