6 citations · 11 across the 19 of their papers we have counts for
20 papers
Matchings and shape-Wilf-Equivalence of sets of patterns of length three II: Quadruples and Quintuples
Sucharita Biswas, Umesh Shankar, Sivaramakrishnan Sivasubramanian
Building on our classification of shape-Wilf-equivalence classes for triples of patterns of length three, we complete the classification for quadruples and quintuples. The larger p…
Matchings and shape-Wilf-Equivalence of sets of patterns of length three I: Triples
Sucharita Biswas, Umesh Shankar, Sivaramakrishnan Sivasubramanian
Permutation pattern avoidance on Ferrers boards has become a central topic in enumerative combinatorics with important connections to matchings, set partitions, and other combinato…
Ordinal and disjoint sums of partially ordered patterns
Sucharita Biswas, Umesh Shankar, Sivaramakrishnan Sivasubramanian
Partially ordered patterns (POPs) generalize the classical notion of permutation patterns within the framework of pattern avoidance. Building on recent work by Burstein, Han, Kitae…
A descent-excedance correspondence in colored permutation groups
Hiranya Kishore Dey, Umesh Shankar, Sivaramakrishnan Sivasubramanian
It is well known that descents and excedances are equidistributed in the symmetric group. We show that the descent and excedance enumerators, summed over permutations with a fixed…
Unimodality and peak location of the characteristic polynomials of two distance matrices of trees
Rakesh Jana, Iswar Mahato, Sivaramakrishnan Sivasubramanian
Unimodality of the normalized coefficients of the characteristic polynomial of distance matrices of trees are known and bounds on the location of its peak (the largest coefficient)…
Canonical reduced words and signed descent length enumeration in Coxeter groups
Umesh Shankar, Sivaramakrishnan Sivasubramanian
Reifegerste and independently, Petersen and Tenner studied a statistic on permutations in . Two other studied statistics on are…