Zobrazeno 1 - 10
of 13
pro vyhledávání: '"Dimosthenis Drivaliaris"'
Publikováno v:
Boundary Value Problems, Vol 2007 (2007)
We prove a linear and a nonlinear generalization of the Lax-Milgram theorem. In particular, we give sufficient conditions for a real-valued function defined on the product of a reflexive Banach space and a normed space to represent all bounded linear
Externí odkaz:
https://doaj.org/article/a4f62332c8c2485395dde7aa6921b36e
Publikováno v:
Rendiconti del Circolo Matematico di Palermo Series 2. 70:1051-1060
Nearness of an operator A to an operator B, which was introduced by Campanato, yields existence and uniqueness results for operator equations involving A exploiting the solvability of the same equations for B. In this paper we introduce the notion of
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::39ce186388430e06c144b3c8e295a747
https://doi.org/10.1007/s12215-020-00542-1
https://doi.org/10.1007/s12215-020-00542-1
Let $X$ be a Banach space, $A\in B(X)$ and $M$ be an invariant subspace of $A$. We present an alternative proof that, if the spectrum of the restriction of $A$ to $M$ contains a point that is in any given hole in the spectrum of $A$, then the entire
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3bc5a8ea96128f82f1fa9f40eef635ff
http://arxiv.org/abs/2004.11708
http://arxiv.org/abs/2004.11708
Publikováno v:
Journal of Operator Theory. 76:205-218
We show that if the angle of a bounded linear operator on a Ba- nach space, with closed range and closed sum of its range and kernel, is less than �, then its range and kernel are complementary. In finite dimensions and up to rotations this simple
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::5aa41622ab5efa5e738ffc218f7f9c42
https://doi.org/10.7900/jot.2015dec02.2083
https://doi.org/10.7900/jot.2015dec02.2083
We define the angle of a bounded linear operator A along a curve emanating from the origin and use it to characterize range-kernel complementarity. In particular we show that if $$\sigma (A)$$ does not separate 0 from $$\infty $$ , then $$X=R(A)\oplu
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1bfb5de4676dbf60b966c124b0fac229
Publikováno v:
SETN
Collaborative filtering recommender systems make automatic predictions about users' interests by utilizing information collected from similarly minded users in order to recommend new items. However in most practical settings the ratings matrix is ext
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::b2d37906877d7a5e2821fe47c1ce1ac9
https://doi.org/10.1145/3200947.3201009
https://doi.org/10.1145/3200947.3201009
Publikováno v:
Cognitive Computation. 7:86-102
An important problem in the learning process when training feedforward artificial neural networks is the occurrence of temporary minima which considerably slows down learning convergence. In a series of previous works, we analyzed this problem by der
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::371378b4ce99b83f0910b393961ab36b
https://doi.org/10.1007/s12559-014-9263-2
https://doi.org/10.1007/s12559-014-9263-2
Publikováno v:
Integral Equations and Operator Theory. 62:159-167
We present an alternative proof of a characterization, due to M. Lauzon and S. Treil, of subspaces with a common complement in a separable Hilbert space. Our approach is motivated by known results concerning the relative position of two subspaces in
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::26eb149478b161d1157e633ef8d542be
https://doi.org/10.1007/s00020-008-1622-5
https://doi.org/10.1007/s00020-008-1622-5
Publikováno v:
Linear Algebra and its Applications. 429(7):1555-1567
In this paper we characterize EP operators through the existence of different types of factorizations. Our results extend to EP operators existing characterizations for EP matrices and give new characterizations both for EP matrices and EP operators.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2259540beabd29e5d9267688bbb2ac81
Publikováno v:
Scopus-Elsevier
We show that linear operators from a Banach space into itself which satisfy some relaxed strong accretivity conditions are invertible. Moreover, we characterise a particular class of such operators in the Hilbert space case. By doing so we manage to
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d16a7219238f267e7958dceb96d2625d
https://doi.org/10.1017/s0004972700039538
https://doi.org/10.1017/s0004972700039538