應(yīng)yl7703永利官網(wǎng)徐守軍教授邀請(qǐng)，新西蘭奧克我校學(xué)數(shù)學(xué)系Marston Conder教授將于2019年10月17日-10月20日訪問我校并作學(xué)術(shù)報(bào)告。

報(bào)告1：Symmetry and chirality in discrete structures

時(shí) 間：10月17日下午14:30

地 點(diǎn)：榆中校區(qū)天山堂B503

摘 要：Symmetry is pervasive in both nature and human culture. The notion of chirality (or 'handedness') is similarly pervasive, but less well understood. In this lecture, which is dedicated to my late colleague Peter Lorimer, I will talk about a number of situations involving discrete objects that have maximum possible symmetry in their class, or maximum possible rotational symmetry while being chiral. Examples include combinatorial graphs (networks), geometric solids, maps on surfaces, and some other more abstract structures. These will be illustrated by pictures as much as possible.

報(bào)告2：Some new approaches to finding the minimum genus of a graph

時(shí) 間：10月18日上午10:30

地 點(diǎn)：齊云樓911 報(bào)告廳

摘要：The genus of a connected graph $X$ is defined as the smallest genus of those compact orientable surfaces into which $X$ has a 2-cell embedding (breaking up the surface into `faces'). For example, planar graphs are precisely those having genus $0$.

In this talk I'll describe some recent work that helps find the minimum genus of certain graphs (also in the non-orientable case), when traditional methods are not helpful. One new method uses the orbits of the automorphism group of the graph on cycles of small length, as candidates for bounding cycles of faces of the embedding.

This turned out to be helpful in finding the small genus embeddings of several graphs of interest, and then in combination with two other new approaches for eliminating smaller genera (using independence numbers and integer linear programming), led to the answers to a many open questions.

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報(bào)告人簡(jiǎn)介

Marston Conder院士，是一位國(guó)際聲望極高的數(shù)學(xué)家，國(guó)際代數(shù)圖論方向領(lǐng)頭人，現(xiàn)任新西蘭奧克我校學(xué)杰出教授，新西蘭科學(xué)院院士。曾任新西蘭皇家科學(xué)院院長(zhǎng)、新西蘭皇家學(xué)會(huì)副主席、新西蘭數(shù)學(xué)會(huì)理事長(zhǎng)、新西蘭數(shù)學(xué)及應(yīng)用研究所所長(zhǎng)，奧克我校學(xué)副校長(zhǎng)、代數(shù)領(lǐng)域頂級(jí)期編委。2014年獲新西蘭最高科學(xué)獎(jiǎng)，即皇家學(xué)會(huì)。已發(fā)表SCI論文120余篇，其中多篇發(fā)表在數(shù)學(xué)領(lǐng)域頂級(jí)期刊，被SCI引用700余次，平均引用率為6.72，h-index為11。主要從事群論、組合論、代數(shù)計(jì)算、地圖、多面體等領(lǐng)域研究。

甘肅省應(yīng)用數(shù)學(xué)與復(fù)雜系統(tǒng)省級(jí)重點(diǎn)實(shí)驗(yàn)室

yl7703永利官網(wǎng)

萃英學(xué)院

2019年10月16日