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A linear operator : between two topological vector spaces (TVSs) is called a bounded linear operator or just bounded if whenever is bounded in then () is bounded in . A subset of a TVS is called bounded (or more precisely, von Neumann bounded ) if every neighborhood of the origin absorbs it.
A T ∈ L(H) is a Fredholm operator if and only if T is invertible modulo compact perturbation, i.e. TS = I + C 1 and ST = I + C 2 for some bounded operator S and compact operators C 1 and C 2. In other words, an operator T ∈ L(H) is Fredholm, in the classical sense, if and only if its projection in the Calkin algebra is invertible.
Since the graph of T is closed, the proof reduces to the case when : is a bounded operator between Banach spaces. Now, T {\displaystyle T} factors as X → p X / ker T → T 0 im T ↪ i Y {\displaystyle X{\overset {p}{\to }}X/\operatorname {ker} T{\overset {T_{0}}{\to }}\operatorname {im} T{\overset {i}{\hookrightarrow }}Y} .
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In mathematics, and specifically in operator theory, a positive-definite function on a group relates the notions of positivity, in the context of Hilbert spaces, and algebraic groups. It can be viewed as a particular type of positive-definite kernel where the underlying set has the additional group structure.
The first inequality (that is, ‖ ‖ < for all ) states that the functionals in are pointwise bounded while the second states that they are uniformly bounded. The second supremum always equals ‖ ‖ (,) = ‖ ‖, ‖ ‖ and if is not the trivial vector space (or if the supremum is taken over [,] rather than [,]) then closed unit ball can be replaced with the unit sphere
A bounded operator: is not a bounded function in the sense of this page's definition (unless =), but has the weaker property of preserving boundedness; bounded sets are mapped to bounded sets (). This definition can be extended to any function f : X → Y {\displaystyle f:X\rightarrow Y} if X {\displaystyle X} and Y {\displaystyle Y} allow for ...
Pam works as a call center operator for 911 emergencies. They together have a daughter, Cassie, whose custody is with Pam for the time being, till they are officially divorced. One day, a notorious criminal, Richard (Ving Rhames), kidnaps Cassie and calls 911 only to connect with Pam, whom he wants to send her estranged husband, Jeremy, to ...