Continued fractions for cycle-alternating permutations

被引:0
|
作者
Deb, Bishal [1 ,2 ,3 ]
Sokal, Alan D. [1 ,4 ]
机构
[1] UCL, Dept Math, London WC1E 6BT, England
[2] Sorbonne Univ, CNRS, Lab Probabil Stat & Modelisat LPSM, Paris, France
[3] Univ Paris, CNRS, Lab Probabil Stat & Modelisat, Paris, France
[4] NYU, Dept Phys, New York, NY 10003 USA
来源
RAMANUJAN JOURNAL | 2024年 / 65卷 / 03期
关键词
Permutation; Cycle-alternating permutation; Alternating cycle; Laguerre digraph; Alternating Laguerre digraph; Secant numbers; Tangent numbers; Continued fraction; S-fraction; Dyck path; SERIES EXPANSION COEFFICIENTS; COMBINATORIAL INTERPRETATION; ELLIPTIC FUNCTIONS; RECURRENCE;
D O I
10.1007/s11139-024-00905-7
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
A permutation is said to be cycle-alternating if it has no cycle double rises, cycle double falls or fixed points; thus each index i is either a cycle valley (sigma(-1)(i) > i < sigma(i). We find Stieltjes-type continued fractions for some multivariate polynomials that enumerate cycle-alternating permutations with respect to a large (sometimes infinite) number of simultaneous statistics that measure cycle status, record status, crossings and nestings along with the parity of the indices. Our continued fractions are specializations of more general continued fractions of Sokal and Zeng. We then introduce alternating Laguerre digraphs, which are generalization of cycle-alternating permutations, and find exponential generating functions for some polynomials enumerating them. We interpret the Stieltjes-Rogers and Jacobi-Rogers matrices associated to some of our continued fractions in terms of alternating Laguerre digraphs.
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页码:1013 / 1060
页数:48
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