Geometry, Algebra and Topology Seminar 
	Speaker: Chengyong Du, Sichuan Normal University
	Title: Elementary differential topology of
orbifold groupoid 
	Abstract:We consider elementary differential
topology of orbifold groupoid (orbi-groupoid), such as the the concept of
sub-orbi-groupoid, orbi-bundles, transversality of orbifold maps, Riemannian
metric, tubular neighborhood of sub-orbi-groupoids. These properties are very necessary
and useful for studying symplectic orbi-groupoids and their Gomov-Witten
theories. 
	Time:   3:30pm--5:30pm Tuesday, Dec 15, 2015 
	Place:  X2415 , Xipu campus at SWJTU  
	You are welcome to attend!