Some simple bijections involving lattice walks and ballot sequences

Some statistics on permutations avoiding generalized patterns

Some statistics on restricted 132 involutions

Some Two Color, Four Variable Rado Numbers

Some unsolved problems on cycles

Some variants of the exponential formula, with application to the multivariate Tutte polynomial (alias Potts model)

Some work on a problem of Marco Buratti

Sort-Invariant Non-Messing-Up

Sortable elements and Cambrian lattices

Sortable Elements for Quivers with Cycles

Sortable elements in infinite Coxeter groups

Sorting a Permutation by block moves

Sorting and preimages of pattern classes

Sorting by Placement and Shift

Sorting orders, subword complexes, Bruhat order and total positivity

Space crossing numbers

Spanning Forests and the Golden Ratio

Spanning Forests of a Digraph and Their Applications

Spanning trees and a conjecture of Kontsevich

Spanning trees and line graph eigenvalues