Hilbert space H, the compact operators are the closure of the finite rank operators in the uniform operator topology. In general, operators on infinite-dimensional...
13 KB (2,284 words) - 06:51, 17 June 2025
limit of finite-rank operators, so that the class of compact operators can be defined alternatively as the closure of the set of finite-rank operators in...
17 KB (2,659 words) - 02:46, 17 July 2025
Sturm–Liouville theory, Integral equations, Fredholm theory Compact operators, Isospectral operators, Completeness Spectral geometry Spectral graph theory List of functional...
32 KB (4,686 words) - 19:13, 8 July 2025
spaces. In general, the spectral theorem identifies a class of linear operators that can be modeled by multiplication operators, which are as simple as...
25 KB (3,852 words) - 23:00, 22 April 2025
Hilbert–Schmidt operator, hence in particular is compact. V has no eigenvalues and therefore, by the spectral theory of compact operators, its spectrum...
2 KB (256 words) - 23:09, 26 May 2024
general operators on infinite-dimensional spaces often requires a genuinely different approach. For example, the spectral theory of compact operators on Banach...
29 KB (4,841 words) - 02:28, 16 May 2025
mathematics, operator theory is the study of linear operators on function spaces, beginning with differential operators and integral operators. The operators may...
12 KB (1,638 words) - 00:07, 26 January 2025
operators are important because the spectral theorem holds for them. The class of normal operators is well understood. Examples of normal operators are...
10 KB (1,549 words) - 22:01, 9 March 2025
Fredholm alternative (category Fredholm theory)
a theorem on Fredholm operators. Part of the result states that a non-zero complex number in the spectrum of a compact operator is an eigenvalue. If V...
10 KB (1,467 words) - 15:30, 16 July 2025
this point of view, operator algebras can be regarded as a generalization of spectral theory of a single operator. In general, operator algebras are non-commutative...
5 KB (545 words) - 10:35, 19 July 2025
eigenfunctions which form an orthonormal basis follows from the spectral theorem for compact operators. Finally, note that ( L − z ) − 1 u = α u , L u = ( z +...
31 KB (4,750 words) - 18:47, 13 July 2025
Hilbert space (category Operator theory)
pseudodifferential operators. The spectral theory of unbounded self-adjoint operators is only marginally more difficult than for bounded operators. The spectrum of an...
128 KB (17,476 words) - 20:44, 30 July 2025
greater detail the structure of the proof of Mercer's theorem, particularly how it relates to spectral theory of compact operators. The map K ↦ TK is injective...
12 KB (1,942 words) - 07:23, 18 July 2025
broader sense, the abstract structure of Fredholm's theory is given in terms of the spectral theory of Fredholm operators and Fredholm kernels on Hilbert space...
8 KB (1,314 words) - 05:08, 14 May 2025
mathematics, Fredholm operators are certain operators that arise in the Fredholm theory of integral equations. They are named in honour of Erik Ivar Fredholm...
10 KB (1,609 words) - 17:45, 12 June 2025
such operators appear in scattering theory). The spectral theorem applies only to self-adjoint operators, and not in general to symmetric operators. Nevertheless...
48 KB (8,156 words) - 10:24, 4 March 2025
First notice that K is in L2(X, m), therefore T is compact. By the spectral properties of compact operators, any nonzero λ in σ(T) is an eigenvalue. But it...
2 KB (332 words) - 20:14, 21 May 2024
now known as Sturm–Liouville theory. In modern language, it is an application of the spectral theorem for compact operators due to David Hilbert. In his...
63 KB (9,399 words) - 17:12, 26 February 2025
Projection-valued measure (redirect from Spectral measure)
quantum information theory. Spectral theorem Spectral theory of compact operators Spectral theory of normal C*-algebras Conway 2000, p. 41. Hall 2013, p. 138...
16 KB (2,507 words) - 23:54, 11 April 2025
Resolvent formalism (redirect from Compact resolvent)
functional calculus Spectral theory Compact operator Laplace transform Fredholm theory Liouville–Neumann series Decomposition of spectrum (functional...
6 KB (871 words) - 01:13, 3 July 2024
Dmitri; Vassilevich, Dmitri (2011), Operators, Geometry and Quanta: Methods of Spectral Geometry in Quantum Field Theory, Theoretical and Mathematical Physics...
2 KB (303 words) - 09:20, 16 July 2024
integral operators are both continuous and compact. The concept of a Hilbert–Schmidt integral operator may be extended to any locally compact Hausdorff...
3 KB (330 words) - 01:06, 25 March 2025
summable spectral triple is a spectral triple (A, H, D) such that a.D for any a in A has a compact resolvent which belongs to the class of Lp+-operators for...
13 KB (1,959 words) - 20:14, 4 February 2025
Atkinson's theorem (category Fredholm theory)
Ker(T) is contained in an eigenspace of C2, which is finite-dimensional (see spectral theory of compact operators). Therefore, Ker(T) is also finite-dimensional...
4 KB (618 words) - 19:09, 6 April 2025
Harmonic analysis (redirect from Harmonics Theory)
areas as diverse as number theory, representation theory, signal processing, quantum mechanics, tidal analysis, spectral analysis, and neuroscience....
14 KB (1,634 words) - 18:04, 6 March 2025
pseudo-differential operator is an extension of the concept of differential operator. Pseudo-differential operators are used extensively in the theory of partial...
10 KB (1,404 words) - 00:15, 3 August 2025
Banach algebra (redirect from Spectral mapping theorem)
of the algebra of bounded operators on some Hilbert space. Measure algebra: A Banach algebra consisting of all Radon measures on some locally compact...
17 KB (2,598 words) - 09:10, 24 May 2025
C*-algebra (section C*-algebras of compact operators)
theory of unitary representations of locally compact groups, and are also used in algebraic formulations of quantum mechanics. Another active area of...
20 KB (2,830 words) - 09:30, 14 January 2025
Fredholm integral equation (redirect from Fredholm integral equation theory)
Compactness may be shown by invoking equicontinuity, and more specifically the theorem of Arzelà-Ascoli. As an operator, it has a spectral theory that...
8 KB (1,056 words) - 20:02, 29 March 2025
Mathematical operator-value measure of interest in quantum mechanics and functional analysis Spectral theory of compact operators Spectral theorem – Result...
17 KB (3,455 words) - 22:40, 28 March 2023