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路与路的联图P_m∨P_n的(2,1)-全标号 被引量:1
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作者 张苏梅 潘珂 刘庆红 《济南大学学报(自然科学版)》 CAS 北大核心 2009年第3期308-311,共4页
图G的一个k-(2,1)-全标号是一个映射f:V(G)∪E(G)→{1,2,…,k}使得相邻的顶点标不同的号;相邻的边标不同的号;顶点与所关联的边标号数相差至少为2。图G的(2,1)-全标号数λ2T(G)定义为G有一个k-(d,1)-全标号的最小的k值。研究路与路的联... 图G的一个k-(2,1)-全标号是一个映射f:V(G)∪E(G)→{1,2,…,k}使得相邻的顶点标不同的号;相邻的边标不同的号;顶点与所关联的边标号数相差至少为2。图G的(2,1)-全标号数λ2T(G)定义为G有一个k-(d,1)-全标号的最小的k值。研究路与路的联图Pm∨Pn的(2,1)-全标号问题,并给出Pm∨Pn的(d,1)-全标号数的上界。 展开更多
关键词 的联图pm∨Pn k-(2 1)-全标号 (2 1)-全标号数
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两类图的2符号全控制数
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作者 陈维 红霞 《江苏师范大学学报(自然科学版)》 CAS 2019年第2期44-48,共5页
设图G=(V,E)为一个简单图,且δ(G)≥1,令f:V(→){-2,-1,1,2}是图G上的一个函数,如果对任意的顶点v∈V,均有f(N(v))≥1成立,则称f为图G的一个2符号全控制函数.主要用分类讨论方法和穷标法得到路Pm和圈Cm的2符号全控制数的精确值.
关键词 2符号全控制函数 路pm 圈Cm
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Effects of arbuscular mycorrhizal fungi on Solidago canadensis growth are independent of nitrogen form
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作者 Dan-Lei Song Yu-Fei Zhao +3 位作者 Fang-Ping Tang Yan-Hua Zhang Shu-Qi Zhou Li-Jia Dong 《Journal of Plant Ecology》 SCIE CSCD 2021年第4期648-661,共14页
Aims Invasive plants may alter soil fungal communities in a way that improves their growth.Nitrogen(N)content of soil affects the symbiosis between plants and arbuscular mycorrhizal fungi(AMF),further determining plan... Aims Invasive plants may alter soil fungal communities in a way that improves their growth.Nitrogen(N)content of soil affects the symbiosis between plants and arbuscular mycorrhizal fungi(AMF),further determining plant growth.Yet,it is unclear whether altered AMF communities change the dependence of invasive and native species on N-form,and whether N forms alter the invasive plant–AMF interaction(PSIM).Methods Two synthetic plant communities,including four Solidago canadensis individuals and four native plant species,were inoculated with AMF spores from S.canadensis-invaded soils and adjacent non-invaded soils,and were provided with nitrate,ammonia or glutamate.After their growth,the performance of the two plant communities in treatments of AMF origin and N forms,and the pathways of the N forms affecting S.canadensis growth and PSIM were evaluated.Important Findings Solidago canadensis had no obvious N-form dependence in any of the AMF inoculations.Native plant species showed weak N-form dependence,but invasive AMF could remove their N-form dependence.In the absence of N,AMF did not affect growth of S.canadensis and the native plants.In contrast,with N addition,invasive AMF significantly increased belowground and total biomass of the invasive plants but not those of the native plants.Positive PSIM of S.canadensis was also evidently greater than that of native plant species and was realized through directly or indirectly regulating phenotypic traits including plant height,leaf number and number of rhizomes.Our findings emphasize the importance of plant–AMF interactions and a unique N-acquisition strategy during plant invasions. 展开更多
关键词 PLANT soil interaction inorganic nitrogen organic nitrogen plant invasion PLS-pm Solidago canadensis
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