Title: Iterated star map and its applications to combinatorics
Speaker: Renling Jin（College of Charleston）
Time: Tuesday, May 16, 2024, 14:00-15:00
Location: Mingde Building, B201-1
Abstract: A star map is a bounded elementary embedding from a superstructure V(X) to another superstructure V(Y) where X is a subset of Y. Star map is an important tool in nonstandard analysis which connects standard mathematics to nonstandard mathematics. In this talk, we establish a framework where the star map is actually an embedding from V(X) into V(X) itself. Hence, the map can naturally be iterated. Furthermore, the iteration can be conducted externally as well as internally with distinct merits, respectively. We will demonstrate the strength of this approach by proving some theorems in combinatorics in the framework. This is an on-going joint work with Mauro Di Nasso.
