Efren Ruiz

activity

20052025

most citedEquivalence and stable isomorphism of groupoids, and diagonal-preserving stable isomorphisms of graph C*-algebras and Leavitt path algebras

58 citations · 342 across the 36 of their papers we have counts for

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40 papers · 1 filter

math.OA2025

Diagonal-preserving Isomorphisms of Algebras from Infinite Graphs

Søren Eilers, Efren Ruiz

We establish logical equivalence between statements involving * the Cuntz C*-algebra $O_{\infty}$ with its canonical diagonal; * graph C*-algebras with their canonical diago…

math.OA2020

Amplified graph C*-algebras II: reconstruction

Søren Eilers, Efren Ruiz, Aidan Sims

Let $E$ be a countable directed graph that is amplified in the sense that whenever there is an edge from $v$ to $w$ , there are infinitely many edges from $v$ to $w$ . We show that $…

math.OA2019★ 2 cited

Geometric classification of isomorphism of unital graph C*-algebras

Sara E. Arklint, Søren Eilers, Efren Ruiz

We geometrically describe the relation induced on a set of graphs by isomorphism of their associated graph C*-algebras as the smallest equivalence relation generated by five types…

math.OA2019★ 7 cited

Refined moves for structure-preserving isomorphism of graph C*-algebras

Søren Eilers, Efren Ruiz

We formalize eight different notions of isomorphism among (unital) graph C*-algebras, and initiate the study of which of these notions may be described geometrically as generated b…

math.OA2018★ 2 cited

The extension problem for graph $C^{*}$ -algebras

Søren Eilers, James Gabe, Takeshi Katsura +2

We give a complete $K$ -theoretical description of when an extension of two simple graph $C^{*}$ -algebras is again a graph $C^{*}$ -algebra.

math.OA2018

The unital Ext-groups and classification of $C^{*}$ -algebras

James Gabe, Efren Ruiz

The semigroups of unital extensions of separable $C^{*}$ -algebras come in two flavours: a strong and a weak version. By the unital $Ext$ -groups, we mean the groups of inv…