On twin and anti-twin words in the support of the free Lie algebra
On two biased graph processes
On Two Bijections from S_n(321) to S_n(132)
On two generalizations of the Alon-Tarsi polynomial method
On two problems in graph Ramsey theory
On Two Related Questions of Wilf Concerning Standard Young Tableaux
On two-point configurations in random set
On types of growth for graph-different permutations
On umbral extensions of Stirling numbers and Dobinski-like formulas
On unavoidable sets of word patterns
On uniform recurrence of HD0l systems
On uniformly generating Latin squares
On Unimodality of Independence Polynomials of some Well-Covered Trees
On unimodality problems in Pascal's triangle
On uniquely k-determined permutations
On uniquely list colorable graphs
On uniqueness of the q-state Potts model on a self-dual family of graphs
On Universal Cycles for Multisets
On Universal Cycles for new Classes of Combinatorial Structures
On Universal Cycles of Labeled Graphs