9 papers
Image Denoising Using Lower Semi-Frames
Hemalatha M, P. Sam Johnson
A blind image denoising framework based on an infinite directional lower semi-frame (DLSF) is proposed for additive white Gaussian noise. The model employs scale-dependent directio…
Characterization of Frame-Related Sequences on Semi-Hilbert Spaces
Hemalatha M, P. Sam Johnson
Let and be positive bounded operators. We investigate reduced weighted adjoints of densely defined closable operators and use the…
A cohomology theory of supercommutative algebras and grading-restricted vertex superalgebras
Paul Johnson, Fei Qi
This paper constructs the cohomology theory for grading-restricted vertex superalgebras, generalizing Yi-Zhi Huang's cohomology theory of grading-restricted vertex algebras. To sim…
Direct Sum of Lower Semi-Frames in Hilbert Spaces
Hemalatha M, P. Sam Johnson, Harikrishnan P. K
In this paper, structural properties of lower semi-frames in separable Hilbert spaces are explored with a focus on transformations under linear operators (may be unbounded). Also,…
Some spectral results for certain positive operators in Hilbert Spaces
Rashid A., P Sam Johnson
This paper investigates spectral properties of certain classes of positive operators originated from different matrices appeared in linear complementarity problem. These positive o…
Characterizations of closed EP operators on Hilbert spaces
Arup Majumdar, P. Sam Johnson
In this paper, we present intriguing findings that characterize both the closed (unbounded) and bounded EP operators on Hilbert spaces. Additionally, we demonstrate the result $γ(T…
The Moore-Penrose inverses of unbounded closable operators and the Cartesian product of closed operators in Hilbert spaces
Arup Majumdar, P. Sam Johnson
In this paper, we present some interesting results to characterize the Moore-Penrose inverses of unbounded closable operators and the Cartesian product of closed operators in Hilbe…
Hyers-Ulam Stability of Unbounded Closable Operators in Hilbert Spaces
Arup Majumdar, P. Sam Johnson, Ram N. Mohapatra
In this paper, we discuss the Hyers-Ulam stability of closable (unbounded) operators with several interesting examples. We also present results pertaining to the Hyers-Ulam stabili…
A formula of -spectral radius for -adjoint operators on semi-Hilbertian spaces
Arup Majumdar, P. Sam Johnson
In this paper, we prove the relation , where is a positive semidefin…