## Electronic Communications in Probability

### On the existence of continuous processes with given one-dimensional distributions

#### Abstract

Let $\mathcal{P}$ be the collection of Borel probability measures on $\mathbb{R}$, equipped with the weak topology, and let $\mu :[0,1]\rightarrow \mathcal{P}$ be a continuous map. Say that $\mu$ is presentable if $X_{t}\sim \mu _{t}$, $t\in [0,1]$, for some real process $X$ with continuous paths. It may be that $\mu$ fails to be presentable. Hence, firstly, conditions for presentability are given. For instance, $\mu$ is presentable if $\mu _{t}$ is supported by an interval (possibly, by a singleton) for all but countably many $t$. Secondly, assuming $\mu$ presentable, we investigate whether the quantile process $Q$ induced by $\mu$ has continuous paths. The latter is defined, on the probability space $((0,1),\mathcal{B} (0,1),\mbox{Lebesgue measure} )$, by $Q_{t}(\alpha )=\inf \, \bigl \{x\in \mathbb{R} :\mu _{t}(-\infty ,x]\ge \alpha \bigl \} \quad \quad \mbox{for all } t\in [0,1]\mbox{ and } \alpha \in (0,1).$ A few open problems are discussed as well.

#### Article information

Source
Electron. Commun. Probab., Volume 24 (2019), paper no. 46, 9 pp.

Dates
Accepted: 2 July 2019
First available in Project Euclid: 28 August 2019

https://projecteuclid.org/euclid.ecp/1566957630

Digital Object Identifier
doi:10.1214/19-ECP255

Zentralblatt MATH identifier
07107310

#### Citation

Pratelli, Luca; Rigo, Pietro. On the existence of continuous processes with given one-dimensional distributions. Electron. Commun. Probab. 24 (2019), paper no. 46, 9 pp. doi:10.1214/19-ECP255. https://projecteuclid.org/euclid.ecp/1566957630

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