We present a family of number sequences which interpolates between the sequences Bn, of Bell numbers, and n!. It is defined in terms of permutations with forbidden patterns or subsequences. The introduction, as a parameter, of the number m of right-to-left minima yields an interpolation between Stirling numbers of the second kind S(n,m) and of the first kind (signless) c(n,m). Moreover, q-counting the restricted permutations by special inversions gives an interpolation between variants of the usual q-analogues of these numbers.
Stirling numbers interpolation using permutations with forbidden subsequences / G. LABELLE; P. LEROUX ; E. PERGOLA; R. PINZANI. - In: DISCRETE MATHEMATICS. - ISSN 0012-365X. - STAMPA. - 246:(2002), pp. 177-195. [10.1016/S0012-365X(01)00257-6]
Stirling numbers interpolation using permutations with forbidden subsequences
PERGOLA, ELISA;PINZANI, RENZO
2002
Abstract
We present a family of number sequences which interpolates between the sequences Bn, of Bell numbers, and n!. It is defined in terms of permutations with forbidden patterns or subsequences. The introduction, as a parameter, of the number m of right-to-left minima yields an interpolation between Stirling numbers of the second kind S(n,m) and of the first kind (signless) c(n,m). Moreover, q-counting the restricted permutations by special inversions gives an interpolation between variants of the usual q-analogues of these numbers.I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.