세미나/포럼
[세미나/포럼] [2016.02.29 월] 2016학년도 제3회 수학과 위상조합세미나 안내
- 세미나/포럼
- 교내
- 윤혜주
- 2016-02-18
2016학년도 제3회 위상조합세미나 일정을 안내해 드립니다.
일 시 :2월 29일(월) 15:00-17:00
장 소: 아주대학교 팔달관 621호
[Talk 1]
시 간: 오후 3:00 - 3:50
연 사: Kenta Ozeki (National Institute of Informatics, Japan)
제 목: Polychromatic colorings of plane graphs and graphs on surfaces
초 록: For a graph $G$ on a surface (or on the plane), a {\em polychromatic $k$-coloring} of $G$ is a vertex $k$-coloring such that there appear all $k$ colors in every face of $G$. In this talk, I will show several results fro the case $k = 3$ or $4$, including a necessary and sufficient conditions for the case of quadrangulations.
This is joint work with Atsuhiro Nakamoto (Yokohama National University) and Kenta Noguchi (Tokyo Denki University).
[Talk 2]
시 간: 오후 4:00 - 4:50
연 사: Michitaka Furuya (Tokyo University of Science, Japan)
제 목: Some approaches for comparing rainbow domination numbers
초 록: Let $k\geq 1$ be an integer, and set $[k]:=\{1,\ldots ,k\}$.
Let $G$ be a graph. A function $f:V(G)\rightarrow 2^{[k]}$ is a $k$-rainbow dominating function (or $k$-RDF) of $G$ if $\bigcup _{y\in N_{G}(x)}f(y)=[k]$ for all $x\in V(G)$ with $f(x)=\emptyset $. The minimum weight $w(f):=\sum _{x\in V(G)}|f(x)|$ of a $k$-RDF $f$ of $G$ is called the $k$-rainbow domination number and denoted by $\gamma _{rk}(G)$. It has been known that every graph $G$ satisfies $\gamma _{rk}(G)\leq |V(G)|$, and for $k\geq 4$, the bound is sharp because $\gamma _{rk}(P_{n})=n$. In particular, when we focus on upper bounds for the rainbow domination, there is no difference between $\gamma _{rk}$ and $\gamma _{rk'}$ with $k\not= k'$. In this talk, we give some approaches for finding potentially difference.
위상조합세미나는 아주대 수학과에서 위상, 조합 관련 주제로 매달 2-3회 정도 정규적으로 열리는 세미나 입니다.
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