Speaker: Prof. Dominique Foata (Strasbourg)

Title: "Entringer numbers and Poupard Calculus"

Time and Location: Wednesday, November 13, 2013
                   2:00 pm, Seminar room pond, RISC, Hagenberg

Abstract: Refinements of the celebrated tangent and secant numbers
give rise to bivariate statistical distributions that can be expressed,
either by a finite difference equation system, or by a three-variate
exponential generating function. The underlying combinatorial sets,
counted by tangent and secant numbers, are the alternating permutations,
or the André permutations of the two kinds, or still the binary
increasing trees. Emphasis will be made on the calculation of the involved
series.