Partitions with parts in a finite set and with parts outside a finite set.
Pattern avoidance classes and subpermutations.
Permutations with inversions.
Probability that an element of a finite group has a square root
Let G be a finite group of even order. We give some bounds for the probability p(G) that a randomly chosen element in G has a square root. In particular, we prove that p(G) ≤ 1 - ⌊√|G|⌋/|G|. Moreover, we show that if the Sylow 2-subgroup of G is not a proper normal elementary abelian subgroup of G, then p(G) ≤ 1 - 1/√|G|. Both of these bounds are best possible upper bounds for p(G), depending only on the order of G.
Profiles of permutations.
Random walk on a building of type Ãr and brownian motion of the Weyl chamber
In this paper we study a random walk on an affine building of type Ãr, whose radial part, when suitably normalized, converges toward the brownian motion of the Weyl chamber. This gives a new discrete approximation of this process, alternative to the one of Biane (Probab. Theory Related Fields89 (1991) 117–129). This extends also the link at the probabilistic level between riemannian symmetric spaces of the noncompact type and their discrete counterpart, which had been previously discovered by Bougerol...
Rare events and conditional events on random strings.
Regularly spaced subsums of integer partitions
Sequences with Adjacent Elements Unequal
Some general problems on the number of parts in partitions
Some Parity Statistics in Integer Partitions
We study integer partitions with respect to the classical word statistics of levels and descents subject to prescribed parity conditions. For instance, a partition with summands may be enumerated according to descents while tracking the individual parities of and . There are two types of parity levels, E = E and O = O, and four types of parity-descents, E > E, E > O, O > E and O > O, where E and O represent arbitrary even and odd summands. We obtain functional equations and explicit...
Some properties of associated Stirling numbers.
Some results on derangement polynomials
We study moments of the difference concerning derangement polynomials . For the first moment, we obtain an explicit formula in terms of the exponential integral function and we show that it is always negative for . For the higher moments, we obtain a multiple integral representation of the order of the moment under computation.
Sorting classes.
Strings with maximally many distinct subsequences and substrings.
Sums involving moments of reciprocals of binomial coefficients.
The asymptotic behavior of elementary symmetric functions on a probability distribution.
The asymptotic number of set partitions with unequal block sizes.
The enumeration of simple permutations.
The fraction of subspaces of with a specified number of minimal weight vectors is asymptotically Poisson.