Ivan Penkov

activity

20212026

collaborators

4 papers

math.GM2026

Complex numbers: uncommon knowledge

Ivan Penkov

In this note we unveil some subfields of the field of complex numbers which are well known to specialists, but seem to remain hidden for a wider mathematical audience. The existenc…

math.AG2025

Linear embeddings of grassmannians and ind-grassmannians

Ivan Penkov, Valdemar Tsanov

By a grassmannian we understand a usual complex grassmannian or possibly an orthogonal or symplectic grassmannian. We classify, with few exceptions, linear embeddings of grassmanni…

math.NT2025

Prime numbers and dynamics of the polynomial $x^{2} - 1$

Ivan Penkov, Michael Stoll

Let $n \in Z_{⩾ 2}$ . By $P (n)$ we denote the set of all prime divisors of the integers in the sequence $n, n^{2} - 1, (n^{2} - 1)^{2} - 1, \dots$ . We ask whether the set $P(n)…

math.AG2021

Automorphism groups of ind-varieties of generalized flags

Mikhail Ignatev, Ivan Penkov

We compute the group of automorphisms of an arbitrary ind-variety of (possibly isotropic) generalized flags. Such an ind-variety is a homogeneous ind-space for one of the ind-group…

Complex numbers: uncommon knowledge

Linear embeddings of grassmannians and ind-grassmannians

Prime numbers and dynamics of the polynomial x2−1

Automorphism groups of ind-varieties of generalized flags

Prime numbers and dynamics of the polynomial $x^{2} - 1$