P. Muthukumar

activity

20242026

collaborators

4 papers

math.FA2026

Singular inner eigenfunctions of composition operators

V. A. Anjali, P. Muthukumar, P. Shankar

This paper characterizes all the singular inner eigenfunctions of the composition operators $C_{ϕ}$ that arise from discrete measures, when $ϕ$ is an automorphism of unit disk. By es…

math.FA2025

Multiplicative operators on analytic function spaces

Kanha Behera, Junming Liu, P. Muthukumar

H. J. Schwartz proved in his thesis (1969) that a nonzero bounded operator on Hardy spaces $(H^{p}, 1 \leq p \leq \infty)$ is almost multiplicative if and only if it is a composition op…

math.CV2024

Automorphisms of subalgebras of bounded analytic functions

Kanha Behera, Rahul Maurya, P. Muthukumar

Let $H^{\infty}$ denote the algebra of all bounded analytic functions on the unit disk. It is well-known that every (algebra) automorphism of $H^{\infty}$ is a composition operator ind…

math.FA2024

Composition operators between Beurling subspaces of Hardy space

V. A. Anjali, P. Muthukumar, P. Shankar

V. Matache (J. Operator Theory 73(1):243--264, 2015) raised an open problem about characterizing composition operators $C_{ϕ}$ on the Hardy space $H^{2}$ and nonzero singular measures…