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COMBINATORICS
1999
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13 years 3 months ago
A Criterion for Unimodality
We show that if P(x) is a polynomial with nondecreasing, nonnegative coefficients, then the coefficient sequence of P(x + 1) is unimodal. Applications are given.
George Boros, Victor H. Moll
TCS
2008
13 years 3 months ago
Another proof of Soittola's theorem
Soittola's theorem characterizes R+- or N-rational formal power series in one variable among the rational formal power series with nonnegative coefficients. We present here a...
Jean Berstel, Christophe Reutenauer