Alexandru Chirvasitu

collaborators

8 papers

math.OA2026

Uniformity and isotypic smallness for quantum-group representations

Compact-group representations on Banach spaces are known to be norm-continuous precisely when they have finite spectra. For a quantum group with continuous-function algebra $\mathc…

math.GR2026

Action principality as a Lie-group certificate

Alexandru Chirvasitu

A continuous action $G ↻ X$ of a topological group is principal if its isotropy groups are all conjugate to $H \leq G$ and the quotient map…

math.SP2026

Eigenvalue collision and exotic preservers on semisimple operators

Alexandru Chirvasitu

We classify $n \times n$ -matrix-valued continuous commutativity and spectrum preservers defined on spaces of (a) normal, (b) semisimple and (c) arbitrary $n \times n$ matrices with s…

math.AT2026

Equivariant compactifications, trivial embeddability and finite type

Alexandru Chirvasitu

We characterize finite-type $G$ -principal $U$ -equivariant bundles on normal $U$ -spaces for compact Lie groups $U$ and $G$ , in several w…

math.QA2026

Irremediably singular quantum branched covers

Alexandru Chirvasitu

We prove that the Natsume-Olsen non-commutative spheres $S_{I^}^{2 n - 1} ¸$ dualize for rational deformation parameters to provide examples of quantum branched covers over their…

math.FA2026

Obstructed subhomogeneous-bundle extensions and embeddings

Alexandru Chirvasitu

We address a number of problems concerning the (im)possibility of either extending locally trivial subbundles of possibly singular Banach/ $C^{*}$ bundles globally, embedding subhomog…