arXiv subjects
Publications and source records attributed to Ehyter M. Martín-González.
Given that extinction in a bisexual population is certain, we study a way to approximate the time when this extinction occurs. Our study is based on standard tools from Extreme Value Theory, which in practice are very easy to implement. We present the theoretical results derived from our study and provide a few numerical examples of such results.
In this paper we propose a model to study the appropriation of knowledge of one student in a non-collaborative online class. We formulate a stochastic model based on the quality of the teacher's class and the affinity of the student to understand the sessions, under the assumption that previous sessions have some influence in the understanding of the next sessions. This assumption implies that the process is not even a Markov process. This kind of situation appears in seminars and classes with many different sessions. We derive some recursive expressions for the distribution of the number of sessions that the student comprehends. Furthermore, we study the convergence of this distribution and study the speed of this convergence through some numerical examples.
We study the distribution of the negative Wiener-Hopf factor for a class of two-sided jumps Lévy processes whose positive jumps have a rational Laplace transform. The positive Wiener-Hopf factor for this class of processes was studied by Lewis and Mordecki (2008). Here we obtain a formula for the Laplace transform of the negative Wiener-Hopf factor, as well as an explicit expression for its probability density, which is in terms of sums of convolutions of known functions. Under additional regularity conditions on the Lévy measure of the studied processes, we also provide asymptotic results as $u\to-\infty$ for the distribution function $F(u)$ of the negative Wiener-Hopf factor. We illustrate our results in some particular examples.