Genera are homomorphisms from the cobordism ring to a commutative ring like the real numbers or complex numbers. In the first part of the talks the rigidity property of genera is explained and the elliptic genus will be introduced as the universal genus with respect to the rigidity property. In the second part, after describing orbifolds and orbifold elliptic genera, I will discuss the rigidity of orbifold elliptic genera.
Genera are homomorphisms from the cobordism ring to a commutative ring like the real numbers or complex numbers. In the first part of the talks the rigidity property of genera is explained and the elliptic genus will be introduced as the universal genus with respect to the rigidity property. In the second part, after describing orbifolds and orbifold elliptic genera, I will discuss the rigidity of orbifold elliptic genera.