¿Todos somos Josef K.?

Recurrence Relations for Elliptic Sequences : Every Somos 4 Is a Somos K

In his ‘Memoir on Elliptic Divisibility Sequences’, Morgan Ward’s definition of the said sequences has the remarkable feature that it does not become at all clear until deep into the paper that there exist nontrivial such sequences. Even then, Ward’s proof of coherence of his definition relies on displaying a sequence of values of quotients of Weierstraß σ -functions. We give a direct proof of ...

Josef Richter

A New Family of Somos-like Recurrences

We exhibit a three parameter infinite family of quadratic recurrence relations inspired by the well known Somos sequences. For one infinite subfamily we prove that the recurrence generates an infinite sequence of integers by showing that the same sequence is generated by a linear recurrence (with suitable initial conditions). We also give conjectured relations among the three parameters so that...

Arguments in English Josef

Despite the idiosyncratic properties of null-complement phenomena observed by Fillmore (1986), Lambrecht and Lemoine (2005), and others, many researchers have pursued large-scope, single-factor explanations of the distributional and interpretive restrictions on null complements—in particular, explanations based on Aktionsart (Rappaport Hovav and Levin 1998) and selectional restrictions (Resnik ...

Todos Cuentan: Cultivating Diversity in Combinatorics.

In nine years the Combinatorics Initiative between San Francisco State University (SFSU) and the nation of Colombia has built an active community of more than two hundred mathematicians, most of whom are members of underrepresented groups in mathematics. More than fifty have pursued PhDs in mathematics, while others continue to be mathematics users, enthusiasts, and ambassadors in other fields ...