19 citations · 69 across the 13 of their papers we have counts for
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math.CO2003★ 8 cited
A combinatorial derivation of the number of labeled forests
David Callan
Lajos Takacs gave a somewhat formidable alternating sum formula for the number of forests of unrooted trees on labeled vertices. Here we use a weight-reversing involution on su…
math.CO2003
A uniformly distributed parameter on a class of lattice paths
David Callan
Let G_n denote the set of lattice paths from (0,0) to (n,n) with steps of the form (i,j) where i and j are nonnegative integers, not both 0. Let D_n denote the set of paths in G_n…
math.CO2003★ 9 cited
Counting stabilized-interval-free permutations
David Callan
A stabilized-interval-free (SIF) permutation on [n]={1,2,...,n} is one that does not stabilize any proper subinterval of [n]. By presenting a decomposition of an arbitrary permutat…