3 papers
math.CO2026
Wilf Equivalence for Length-Three Patterns and Flat POPs, and a Conjecture of Qiu and Remmel
Shiqi Cao, Sergey Kitaev, Yuxin Wu
It is well known that, for each classical pattern of length 3, the number of -avoiding permutations of length is the th Catalan number, and numerous bijections betwee…
math.CO2026
Counting permutations avoiding two flat partially ordered patterns
Shiqi Cao, Huihua Gao, Sergey Kitaev +1
Partially ordered patterns (POPs) play an important role in the study of permutation patterns, providing a convenient framework for describing large families of classical patterns.…
math.CO2026
Dowling's polynomial conjecture for independent sets of matroids
Shiqi Cao, Keyi Chen, Yitian Li +1
The celebrated Mason's conjecture states that the sequence of independent set numbers of any matroid is log-concave, and even ultra log-concave. The strong form of Mason's conjectu…