We give an instance of Stembridge's q = -1 phenomenon for pattern- avoiding permutations. In particular, we show that setting q = -1 in the generating function for 132-avoiding permutations with respect to the statistic rsg returns the number of 132-avoiding involutions.

Author Bio

Xin Chen am a mathematics major at Carleton College. The paper presents the result of the research under the supervision of hi faculty advisor Eric S. Egge with financial support from the Carleton Kolenkow/Reitz fellowship during winter 2010.