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  • articleNo Access

    Tight Toughness, Isolated Toughness and Binding Number Bounds for Some Factors and Some Factor-Deleted Graphs

    For a set 𝒟 of connected graphs, a spanning subgraph F of a graph G is called an 𝒟-factor if each component of F is isomorphic to a member of 𝒟. In this paper, we obtain a sufficient condition with regard to tight toughness, isolated toughness and binding number bounds to guarantee the existence of a {K1,1,K1,2,Cn|n3}-factor, two sufficient conditions to guarantee the existence of a P3-factor in a bipartite graph and some sufficient conditions for {K1,j|1jk}-factor deleted graph and a P2-factor deleted graph.

  • articleNo Access

    Tight isolated toughness bound for fractional (a,b,m)-deleted graphs

    A graph G is a fractional (a,b,m)-deleted graph if deleting any m edges from G, the resulting subgraph still admits a fractional [a,b]-factor. As an exclusive graph-based parameter, isolated toughness and its variant are utilized to measure the vulnerability of networks which are modelled by graph topology structures. Early studies have shown the inherent connection between isolated toughness and the existence of fractional factors in specific settings. This paper provides a theoretical perspective on the sufficient conditions for fractional (a,b,m)-deleted graphs with respect to isolated toughness and its variant. The sharpness of the given isolated toughness bounds is explained by counterexamples.

  • articleNo Access

    Tight Toughness, Isolated Toughness and Binding Number Bounds for the [1,n]-Factors and the {K2,Ci4}-Factors

    Let n2 be an integer. The [1,n]-factor of a graph G is a spanning subgraph F if 1degF(x)n for all xV(G), and the {K2,Ci}-factor is a subgraph whose each component is either K2 or Ci. In this paper, we give the lower bounds with regard to tight toughness, isolated toughness and binding number to guarantee the existence of the [1,n]-factors and {K2,Ci|i4}-factors for a graph.

  • articleNo Access

    Sufficient Conditions of (Isolated) Toughness and Binding Number for the Existence of Component Factors

    For a family of connected graphs , a spanning subgraph L of G is called an -factor if each component of L is isomorphic to a member of . In this paper, sufficient conditions with regard to tight toughness, isolated toughness and binding number bounds to guarantee the existence of the {P2,C3,P5,𝒯(3)}-factor, P2-factor or {P2,C2i+1|ik}-factor for k3 are obtained.

  • articleNo Access

    Tight Toughness, Isolated Toughness and Binding Number Bounds for the Star-Path Factor

    For a set 𝒦 of connected graphs, a spanning subgraph H of G is called a 𝒦-factor if each component of H is isomorphic to a member of 𝒦. In this paper, some sufficient conditions with regard to tight toughness, isolated toughness and binding number bounds to guarantee the existence of the {K1,j:1j2k}-factor and {P2,P5}-factor for any graph are obtained.

  • articleFree Access

    Some Existence Theorems on Star Factors

    The {K1,1,K1,2,,K1,k,𝒯(2k+1)}-factor and {K1,2,K1,3,K5}-factor of a graph are a spanning subgraph whose each component is an element of {K1,1,K1,2,,K1,k,𝒯(2k+1)} and {K1,2,K1,3,K5}, respectively, where 𝒯(2k+1) is a special family of trees. In this paper, we obtain a sufficient condition in terms of tight toughness, isolated toughness and binding number bounds to guarantee the existence of a {K1,1,K1,2,,K1,k,𝒯(2k+1)}-factor and {K1,2,K1,3,K5}-factor for any graph.

  • articleFree Access

    Bounds of Two Toughnesses and Binding Numbers for Star Factors

    For a set of connected graphs, a spanning subgraph H of a graph G is an -factor if every component of H is isomorphic to some member of . In this paper, we give a criterion for the existence of tight toughness, isolated toughness and binding number bounds in a graph of a strong 𝒮-star factor, {1,3,,2n1}-factor and f-star factor. Moreover, we show that the bounds of the sufficient conditions are sharp.