TY - RPRT
T1 - On the topological degree of planar maps avoiding normal cones
Y1 - 2019
A1 - Alessandro Fonda
A1 - Giuliano Klun
AB - The classical Poincaré–Bohl theorem provides the exis-tence of a zero for a function avoiding external rays. When the do-main is convex, the same holds true when avoiding normal cones. We consider here the possibility of dealing with nonconvex sets having in-ward corners or cusps, in which cases the normal cone vanishes. This allows us to deal with situations where the topological degree may be di˙erent from ±1.
PB - SISSA
UR - http://preprints.sissa.it/handle/1963/35330
U1 - 35641
U2 - Mathematics
U4 - 1
ER -