EJC
2010
13 years 11 months ago
2010
Each clone C on a fixed base set A determines a quasiorder on the set of all operations on A by the following rule: f is a C-minor of g if f can be obtained by substituting operati...
EJC
2010
13 years 11 months ago
2010
Abstract. We prove that the combinatorial distance between any two reduced expressions of a given permutation of {1, ..., n} in terms of transpositions lies in O(n4), a sharp bound...
EJC
2010
13 years 11 months ago
2010
We consider the number of nodes in the levels of unlabelled rooted random trees and show that the stochastic process given by the properly scaled level sizes weakly converges to th...
EJC
2010
13 years 11 months ago
2010
In this paper, we investigate some properties of partial covers of PG(n, q). We show that a set of q + a hyperplanes, q 81, a < (q - 1)/3, or q > 13 and a (q - 10)/4, that...
EJC
2010
13 years 11 months ago
2010
A classical result of Euler states that the tangent numbers are an alternating sum of Eulerian numbers. A dual result of Roselle states that the secant numbers can be obtained by a...
EJC
2010
13 years 11 months ago
2010
EJC
2010
13 years 11 months ago
2010
We use group theory to construct infinite families of maps on surfaces which are invariant under Wilson's map operations of order 3 but not under the operations of order 2, s...
EJC
2010
13 years 11 months ago
2010
In [11] all locally subquadrangular hyperplanes of finite symplectic and Hermitian dual polar spaces were determined with the aid of counting arguments and divisibility properties...
EJC
2010
13 years 11 months ago
2010
EJC
2010
13 years 11 months ago
2010
Abstract. Motivated by juggling sequences and bubble sort, we examine permutations on the set {1, 2, . . . , n} with d descents and maximum drop size k. We give explicit formulas f...