Lomonosov's invariant subspace theorem
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Lomonosov's invariant subspace theorem is a mathematical theorem from functional analysis concerning the existence of invariant subspaces of a linear operator on some complex Banach space. The theorem was proved in 1973 by the Russian–American mathematician Victor Lomonosov.[1]
Notation and terminology
Let be the space of bounded linear operators from some space
to itself. For an operator
we call a closed subspace
an invariant subspace if
, i.e.
for every
.
Theorem
Let be an infinite dimensional complex Banach space,
be compact and such that
. Further let
be an operator that commutes with
. Then there exist an invariant subspace
of the operator
, i.e.
.[2]
Citations
- ↑ Lomonosov, Victor I. (1973). "Invariant subspaces for the family of operators which commute with a completely continuous operator". Functional Analysis and Its Applications. 7 (3): 213–214. doi:10.1007/BF01080698.
- ↑ Rudin, Walter (1991). Functional Analysis. McGraw-Hill Science/Engineering/Math. p. 269-270. ISBN 978-0070542365.
References
- Rudin, Walter (1991). Functional Analysis. International Series in Pure and Applied Mathematics. Vol. 8 (Second ed.). New York, NY: McGraw-Hill Science/Engineering/Math. ISBN 978-0-07-054236-5. OCLC 21163277.
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