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!