Let G ： Gn,p be a binomial random graph with n vertices and edge probability p = p（n）, and f be a nonnegative integer-valued function defined on V（G） such that 0 〈 a ≤ f（x） ≤ b 〈 np- 2√nplogn for every ...Let G ： Gn,p be a binomial random graph with n vertices and edge probability p = p（n）, and f be a nonnegative integer-valued function defined on V（G） such that 0 〈 a ≤ f（x） ≤ b 〈 np- 2√nplogn for every E V（G）. An fractional f-indicator function is an function h that assigns to each edge of a graph G a number h（e） in [0, 1] so that for each vertex x, we have d^hG（x） = f（x）, where dh（x） = ∑ h（e） is the fractional degree xEe ofx inG. Set Eh = {e ： e e E（G） and h（e） ≠ 0}. IfGh isaspanningsubgraphofGsuchthat E（Gh） = Eh, then Gh is called an fractional f-factor of G. In this paper, we prove that for any binomial random graph Gn,p 2 with p 〉 n^-2/3, almost surely Gn,p contains an fractional f-factor.展开更多
A graph G is f-covered if each edge of G belongs to an f-factor. Some sufficient conditions for a graph to be f-covered are given.Katerinis'and Bermond's results are generalized.
Let G be a graph, and g and f be integer valued functions defined on V(G) which satisfy g(x)≤f(x) and g(x)≡f(x)(mod 2) for all x∈V(G). Then a spanning subgraph F of G is called a {g,g+2,…,f} -factor if deg_F(x)∈{...Let G be a graph, and g and f be integer valued functions defined on V(G) which satisfy g(x)≤f(x) and g(x)≡f(x)(mod 2) for all x∈V(G). Then a spanning subgraph F of G is called a {g,g+2,…,f} -factor if deg_F(x)∈{g(x),g(x)+2,…,f(x)} for all x∈V(G), when g(x)=1 for all x∈V(G), such a factor is called (1,f) -odd-factor. We give necessary and sufficient conditions for a graph G to have a {g,g+2,…,f} -factor and a (1,f) -odd-factor which contains an arbitrarily given edge of G, from that we derive some interesting results.展开更多
基金Supported by NSFSD(No.ZR2013AM001)NSFC(No.11001055),NSFC11371355
文摘Let G ： Gn,p be a binomial random graph with n vertices and edge probability p = p（n）, and f be a nonnegative integer-valued function defined on V（G） such that 0 〈 a ≤ f（x） ≤ b 〈 np- 2√nplogn for every E V（G）. An fractional f-indicator function is an function h that assigns to each edge of a graph G a number h（e） in [0, 1] so that for each vertex x, we have d^hG（x） = f（x）, where dh（x） = ∑ h（e） is the fractional degree xEe ofx inG. Set Eh = {e ： e e E（G） and h（e） ≠ 0}. IfGh isaspanningsubgraphofGsuchthat E（Gh） = Eh, then Gh is called an fractional f-factor of G. In this paper, we prove that for any binomial random graph Gn,p 2 with p 〉 n^-2/3, almost surely Gn,p contains an fractional f-factor.
文摘A graph G is f-covered if each edge of G belongs to an f-factor. Some sufficient conditions for a graph to be f-covered are given.Katerinis'and Bermond's results are generalized.
文摘Let G be a graph, and g and f be integer valued functions defined on V(G) which satisfy g(x)≤f(x) and g(x)≡f(x)(mod 2) for all x∈V(G). Then a spanning subgraph F of G is called a {g,g+2,…,f} -factor if deg_F(x)∈{g(x),g(x)+2,…,f(x)} for all x∈V(G), when g(x)=1 for all x∈V(G), such a factor is called (1,f) -odd-factor. We give necessary and sufficient conditions for a graph G to have a {g,g+2,…,f} -factor and a (1,f) -odd-factor which contains an arbitrarily given edge of G, from that we derive some interesting results.
