Word.ws English Dictionary

commutant lifting theorem

commutant lifting theorem proper noun: a theorem in operator theory, stating that, if T is a contraction on a Hilbert space H, and U is its minimal unitary dilation acting on some Hilbert space K, and R is an operator on H commuting with T, then there is an operator S on K commuting with U such that RTⁿ=P_HSUⁿ|_H;∀n≥0, and ‖S‖=‖R‖. In other words, an operator from the commutant of T can be "lifted" to an operator in the commutant of the unitary dilation of T.

Proper noun

the commutant lifting theorem

  1. A theorem in operator theory, stating that, if T is a contraction on a Hilbert space H, and U is its minimal unitary dilation acting on some Hilbert space K, and R is an operator on H commuting with T, then there is an operator S on K commuting with U such that RTⁿ=P_HSUⁿ|_H;∀n≥0, and ‖S‖=‖R‖. In other words, an operator from the commutant of T can be "lifted" to an operator in the commutant of the unitary dilation of T.

Questions about commutant lifting theorem

What does commutant lifting theorem mean?
Commutant lifting theorem means a theorem in operator theory, stating that, if T is a contraction on a Hilbert space H, and U is its minimal unitary dilation acting on some Hilbert space K, and R is an operator on H commuting with T, then there is an operator S on K commuting with U such that RTⁿ=P_HSUⁿ|_H;∀n≥0, and ‖S‖=‖R‖. In other words, an operator from the commutant of T can be "lifted" to an operator in the commutant of the unitary dilation of T.
What part of speech is commutant lifting theorem?
Commutant lifting theorem is a proper noun.

Words near commutant lifting theorem in the dictionary

  1. commutable
  2. commutableness
  3. commutal
  4. commutals
  5. commutant
  6. commutant lifting theorem
  7. commutants
  8. commutate
  9. commutated
  10. commutates
  11. commutating

Source and license

Adapted from Wiktionary: commutant lifting theorem (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

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