Search results for "010103 numerical & computational mathematics"
showing 10 items of 260 documents
Special elements in a ring related to Drazin inverses
2013
In this paper, the existence of the Drazin (group) inverse of an element a in a ring is analyzed when amk = kan, for some unit k and m; n 2 N. The same problem is studied for the case when a* = kamk-1 and for the fk; s+1g-potent elements. In addition, relationships with other special elements of the ring are also obtained
Lattice of closure endomorphisms of a Hilbert algebra
2019
A closure endomorphism of a Hilbert algebra [Formula: see text] is a mapping that is simultaneously an endomorphism of and a closure operator on [Formula: see text]. It is known that the set [Formula: see text] of all closure endomorphisms of [Formula: see text] is a distributive lattice where the meet of two elements is defined pointwise and their join is given by their composition. This lattice is shown in the paper to be isomorphic to the lattice of certain filters of [Formula: see text], anti-isomorphic to the lattice of certain closure retracts of [Formula: see text], and compactly generated. The set of compact elements of [Formula: see text] coincides with the adjoint semilattice of …
On zeros of characters of finite groups
2018
We survey some results concerning the distribution of zeros in the character table of a finite group and its influence on the structure of the group itself.
Fredholm Spectra and Weyl Type Theorems for Drazin Invertible Operators
2016
In this paper we investigate the relationship between some spectra originating from Fredholm theory of a Drazin invertible operator and its Drazin inverse, if this does exist. Moreover, we study the transmission of Weyl type theorems from a Drazin invertible operator R, to its Drazin inverse S.
Some fourth order CY-type operators with non symplectically rigid monodromy
2012
We study tuples of matrices with rigidity index two in $\Sp_4(\mathbb{C})$, which are potentially induced by differential operators of Calabi-Yau type. The constructions of those monodromy tuples via algebraic operations and middle convolutions and the related constructions on the level differential operators lead to previously known and new examples.
Boundary modulus of continuity and quasiconformal mappings
2012
Let D be a bounded domain in R n , n ‚ 2, and let f be a continuous mapping of D into R n which is quasiconformal in D. Suppose that jf(x) i f(y)j • !(jx i yj) for all x and y in @D, where ! is a non-negative non-decreasing function satisfying !(2t) • 2!(t) for t ‚ 0. We prove, with an additional growth condition on !, that jf(x) i f(y)jC maxf!(jx i yj);jx i yj fi g
Local Spectral Properties Under Conjugations
2021
AbstractIn this paper, we study some local spectral properties of operators having form JTJ, where J is a conjugation on a Hilbert space H and $$T\in L(H)$$ T ∈ L ( H ) . We also study the relationship between the quasi-nilpotent part of the adjoint $$T^*$$ T ∗ and the analytic core K(T) in the case of decomposable complex symmetric operators. In the last part we consider Weyl type theorems for triangular operator matrices for which one of the entries has form JTJ, or has form $$JT^*J$$ J T ∗ J . The theory is exemplified in some concrete cases.
Soft ditopological spaces
2015
We introduce the concept of a soft ditopological space as the "soft Generalization" of the concept of a ditopological space as it is defined in the papers by L.M. Brown and co-authors, see e.g. L. M. Brown, R. Ert?rk, ?. Dost, Ditopological texture spaces and fuzzy topology, I. Basic Concepts, Fuzzy Sets and Systems 147 (2) (2004), 171-199. Actually a soft ditopological space is a soft set with two independent structures on it - a soft topology and a soft co-topology. The first one is used to describe openness-type properties of a space while the second one deals with its closedness-type properties. We study basic properties of such spaces and accordingly defined continuous mappings between…
Truncated modules and linear presentations of vector bundles
2018
We give a new method to construct linear spaces of matrices of constant rank, based on truncated graded cohomology modules of certain vector bundles as well as on the existence of graded Artinian modules with pure resolutions. Our method allows one to produce several new examples, and provides an alternative point of view on the existing ones.
New special function recurrences giving new indefinite integrals
2018
ABSTRACTSequences of new recurrence relations are presented for Bessel functions, parabolic cylinder functions and associated Legendre functions. The sequences correspond to values of an integer variable r and are generalizations of each conventional recurrence relation, which correspond to r=1. The sequences can be extended indefinitely, though the relations become progressively more intricate as r increases. These relations all have the form of a first-order linear inhomogeneous differential equation, which can be solved by an integrating factor. This gives a very general indefinite integral for each recurrence. The method can be applied to other special functions which have conventional …