## Electronic Communications in Probability

- Electron. Commun. Probab.
- Volume 1 (1996), paper no. 2, 7-10.

### A Proof of a Conjecture of Bobkov and Houdré

S. Kwapien, M. Pycia, and W. Schachermayer

#### Abstract

S. G. Bobkov and C. Houdré recently posed the following question on the Internet (Problem posed in Stochastic Analysis Digest no. 15 (9/15/1995)): Let $X,Y$ be symmetric i.i.d. random variables such that $$P(|X+Y|/2 \geq t) \leq P(|X| \geq t),$$ for each $t>0$. Does it follow that $X$ has finite second moment (which then easily implies that $X$ is Gaussian)? In this note we give an affirmative answer to this problem and present a proof. Using a dierent method K. Oleszkiewicz has found another proof of this conjecture, as well as further related results.

#### Article information

**Source**

Electron. Commun. Probab., Volume 1 (1996), paper no. 2, 7-10.

**Dates**

Accepted: 26 February 1996

First available in Project Euclid: 25 January 2016

**Permanent link to this document**

https://projecteuclid.org/euclid.ecp/1453756493

**Digital Object Identifier**

doi:10.1214/ECP.v1-972

**Mathematical Reviews number (MathSciNet)**

MR1386289

**Zentralblatt MATH identifier**

0854.60014

**Subjects**

Primary: 60E05: Distributions: general theory

Secondary: 60E15: Inequalities; stochastic orderings

**Keywords**

Gaussian distribution

**Rights**

This work is licensed under aCreative Commons Attribution 3.0 License.

#### Citation

Kwapien, S.; Pycia, M.; Schachermayer, W. A Proof of a Conjecture of Bobkov and Houdré. Electron. Commun. Probab. 1 (1996), paper no. 2, 7--10. doi:10.1214/ECP.v1-972. https://projecteuclid.org/euclid.ecp/1453756493