摘要
设P_m和C_m分别表示具有m个顶点的路和圈,G是任意的r阶连通图,设m是偶数,把路P_(m-1)的标号为偶数的2^(-1)m个顶点分别与2^(-1)mG每个分支的第i个顶点V_i重迭后的图记为ρ_((m-1)+2^(-1)mr)~G(i),令n=(2m+1)+(m+1)r,把图kρ_n^G(i)的每个分支的一个d(v_i)+1度顶点分别与S_(k+1)的k个1度点重迭后所得到的图记为Y_(kn+1)^(PG),运用图的伴随多项式的性质,首先给出了一类图簇ρ_n^G(i)和Y_(kn+1)^(PG)的伴随多项式.在讨论上述图的伴随多项式的基础上,证明了图ρ_n^G(i)∪G、Y_(kn+1)^(PG)∪(k-1)K_1和Y_(kn+1)^(PG)∪(k-1)K_1∪(k-1)G的伴随多项式的因式分解定理,进而证明了这些图类的补图的色等价性.
We use the symbol Pm to denote a path with n vertices and Cm to denote a cycle with n vertices, and G be a connective graph with r vertices, and let m be an odd number, and let denote by P(m-1)+2^-1^G(i)mr the graph consisting of Pm-1 and 2^-1mG by coinciding 2^-1m vertices are marked "odd " with the ith vertex Vi of every component of 2^-1mG, respectively; Let n (2m + 1)+ (m + 1)r, and let denote by Pkn+1^PG the graph consisting of kρn^G(i)and Sk+1 by coinciding a vertex of degree d(vi) + 1 of every component of k ρn^G(i)with k vertices of degree 1, respectively; By applying the properties of adjoint polynomials, We give and prove the factorizations Theorem of adjoint polynomials of graphs ρn^G(i)and Ykn+1^PG, based on the above discussed several adjoint polynomials of graphs, We prove Chromatically equivalence of the graphs ρn^G(i)∪ G、 Ykn+1^pg∪(k - 1)K1and Ykn+1^PG∪(k-1)K1∪(k-1)G, prove chromatically equivalent graphs of their complements.
出处
《数学的实践与认识》
北大核心
2015年第7期223-230,共8页
Mathematics in Practice and Theory
基金
国家自然科学基金(10671008)
关键词
色多项式
伴随多项式
因式分解
色等价性
chromatic polynomial
adjoint polynomials
factorization
chromatically equiva-lence