by Reifegerste, A..

**Series:** 2002-26, Preprints

- MSC:
- 05A05 Permutations, words, matrices
- 05A15 Exact enumeration problems, generating functions

**Abstract:**

The diagram of a 132-avoiding permutation can easily be characterized: it is simply the diagram of a partition. Based on this fact, we present a new bijection between

132-avoiding and 321-avoiding permutations. We will show that this bijection translates the correspondences between these permutations and Dyck paths given by Krattenthaler and by Billey-Jockusch-Stanley, respectively, to each

other. Moreover, the diagram approach yields simple proofs for some enumerative results concerning forbidden patterns in 132-avoiding permutations.

**Keywords:**

132-avoiding permutation, 321-avoiding permutation, diagram of a permutation, partition, Young diagram, Dyck path, permutation pattern