Permutation Statistics and $q$-Fibonacci Numbers

TL;DR

This paper explores the distribution of Mahonian permutation statistics related to $q$-Fibonacci numbers, providing bijective proofs and connecting various $q$-Fibonacci sequences through pattern-restricted permutations.

Contribution

It introduces new bijective proofs linking $q$-Fibonacci numbers from permutations to those from set partitions, expanding understanding of their combinatorial properties.

Findings

Established bijections between permutation $q$-Fibonacci numbers and classical ones.

Connected permutation statistics to pattern-restricted Fibonacci counts.

Provided combinatorial proofs of $q$-Fibonacci identities.

Abstract

In a recent paper, Goyt and Sagan studied distributions of certain set partition statistics over pattern restricted sets of set partitions that were counted by the Fibonacci numbers. Their study produced a class of $q$-Fibonacci numbers, which they related to $q$-Fibonacci numbers studied by Carlitz and Cigler. In this paper we will study the distributions of some Mahonian statistics over pattern restricted sets of permutations. We will give bijective proofs connecting some of our $q$-Fibonacci numbers to those of Carlitz, Cigler, Goyt and Sagan. We encode these permutations as words and use a weight to produce bijective proofs of $q$-Fibonacci identities. Finally, we study the distribution of some of these statistics on pattern restricted permutations that West showed were counted by even Fibonacci numbers.