Alexandru Chirvasitu

collaborators

36 papers

math.QA2026

Associative/Lie radical (co)invariance under tracial (co)actions

We prove a number of Jacobson/solvable/nilpotent-radical (co)invariance results for finite-dimensional associative or Lie (co)module-algebras over Hopf algebras $H$ , provided the c…

math.AG2026

Coincident Poisson structures on principal-bundle moduli spaces

Alexandru Chirvasitu

Consider a reductive complex algebraic group $G$ equipped with an action by a linearly reductive affine group scheme $K$ . The extension of $p^{*}$ by $\m…

math.QA2026

On the category of Hopf braces

Ana Agore, Alexandru Chirvasitu

Hopf braces are the quantum analogues of skew braces and, as such, their cocommutative counterparts provide solutions to the quantum Yang-Baxter equation. We investigate various pr…

math.CO2026

Rigid ternary relations in finite-dimensional Hilbert-space Grassmannians

Alexandru Chirvasitu

For positive integers $1 \leq r < d < n$ consider subsets $S \subseteq G (r, V)$ of the $r$ -plane Grassmannian of an $n$ -dimensional Hilbert space $V$ saturated in the sense that t…

math.CT2026

Injectivity paucity in AB5 categories of oversize chains

Alexandru Chirvasitu

We construct examples of abelian categories with no non-zero injective (or projective) objects satisfying Grothendieck's AB5 condition. The procedure combines Rickard's examples of…

math.SP2026

The combinatorics of permuting and preserving curve-bound spectra

Alexandru Chirvasitu

We prove that continuous spectrum- and commutativity-preserving maps to $M_{n} (C)$ from the space of normal (real or complex) $n \times n$ , $n \geq 3$ matrices with s…