Log-concavity of infinite product generating functions

نویسندگان

چکیده

Abstract In the 1970s Nicolas proved that coefficients $$p_d(n)$$ pd(n) defined by generating function $$\begin{aligned} \sum _{n=0}^{\infty } p_d(n) \, q^n = \prod _{n=1}^{\infty \left( 1- q^n\right) ^{-n^{d-1}} \end{aligned}$$ xmlns:mml="http://www.w3.org/1998/Math/MathML">∑n=0∞pd(n)qn=∏n=1∞1-qn-nd-1 are log-concave for $$d=1$$ xmlns:mml="http://www.w3.org/1998/Math/MathML">d=1 . Recently, Ono, Pujahari, and Rolen have extended result to $$d=2$$ xmlns:mml="http://www.w3.org/1998/Math/MathML">d=2 Note $$p_1(n)=p(n)$$ xmlns:mml="http://www.w3.org/1998/Math/MathML">p1(n)=p(n) is partition $$p_2(n)=\mathrm{pp}\left( n\right) $$ xmlns:mml="http://www.w3.org/1998/Math/MathML">p2(n)=ppn number of plane partitions. this paper, we invest in properties general d Let $$n \ge 6$$ xmlns:mml="http://www.w3.org/1998/Math/MathML">n≥6 Then almost n divisible 3 strictly log-convex otherwise.

برای دانلود باید عضویت طلایی داشته باشید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Infinite log-concavity: developments and conjectures

Given a sequence (ak) = a0, a1, a2, . . . of real numbers, define a new sequence L(ak) = (bk) where bk = ak − ak−1ak+1. So (ak) is log-concave if and only if (bk) is a nonnegative sequence. Call (ak) infinitely log-concave if L(ak) is nonnegative for all i ≥ 1. Boros and Moll [3] conjectured that the rows of Pascal’s triangle are infinitely log-concave. Using a computer and a stronger version o...

متن کامل

Log-convexity and log-concavity of hypergeometric-like functions

We find sufficient conditions for log-convexity and log-concavity for the functions of the forms a 7→ ∑ fk(a)kx , a 7→ ∑ fkΓ(a + k)x k and a 7→ ∑ fkx k/(a)k. The most useful examples of such functions are generalized hypergeometric functions. In particular, we generalize the Turán inequality for the confluent hypergeometric function recently proved by Barnard, Gordy and Richards and log-convexi...

متن کامل

Matroids and log-concavity

We show that f -vectors of matroid complexes of realizable matroids are strictly log-concave. This was conjectured by Mason in 1972. Our proof uses the recent result by Huh and Katz who showed that the coefficients of the characteristic polynomial of a realizable matroid form a log-concave sequence. We also prove a statement on log-concavity of h-vectors which strengthens a result by Brown and ...

متن کامل

Bell Numbers, Log-concavity, and Log-convexity

Let fb k (n)g 1 n=0 be the Bell numbers of order k. It is proved that the sequence fb k (n)=n!g 1 n=0 is log-concave and the sequence fb k (n)g 1 n=0 is log-convex, or equivalently, the following inequalities hold for all n 0, 1 b k (n + 2)b k (n) b k (n + 1) 2 n + 2 n + 1 : Let f(n)g 1 n=0 be a sequence of positive numbers with (0) = 1. We show that if f(n)g 1 n=0 is log-convex, then (n)(m) (n...

متن کامل

Log-Concavity and Symplectic Flows

We prove the logarithmic concavity of the Duistermaat-Heckman measure of an Hamiltonian (n− 2)-dimensional torus action for which there exists an effective commuting symplectic action of a 2-torus with symplectic orbits. Using this, we show that any symplectic (n− 2)-torus action with non-empty fixed point set which satisfies this additional 2-torus condition must be Hamiltonian.

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: Research in number theory

سال: 2022

ISSN: ['2363-9555', '2522-0160']

DOI: https://doi.org/10.1007/s40993-022-00352-7