Abstract
We prove that the obstruction bundle used to define the cup-product in Chen–Ruan cohomology has a simple representation-theoretic description. The key quantities in this description are the age gradings or degree-shifting numbers of the representations of the local groups of the orbifold. We obtain a Künneth Theorem for Chen–Ruan cohomology as a direct consequence of an elementary property of the age grading, and explain how several other results, including associativity of the cup product, can be proved in a similar way.
Original language | English |
---|---|
Pages (from-to) | 868-878 |
Number of pages | 11 |
Journal | Bulletin of the London Mathematical Society |
Volume | 42 |
Issue number | 5 |
Early online date | 18 Jun 2010 |
DOIs | |
Publication status | Published - Oct 2010 |