# An accuracy improvement in Egorov's theorem.

Publicacions Matemàtiques (2007)

- Volume: 51, Issue: 1, page 77-120
- ISSN: 0214-1493

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topSilva, Jorge Drumond. "An accuracy improvement in Egorov's theorem.." Publicacions Matemàtiques 51.1 (2007): 77-120. <http://eudml.org/doc/41888>.

@article{Silva2007,

abstract = {We prove that the theorem of Egorov, on the canonical transformation of symbols of pseudodifferential operators conjugated by Fourier integral operators, can be sharpened. The main result is that the statement of Egorov's theorem remains true if, instead of just considering the principal symbols in Sm/Sm-1 for the pseudodifferential operators, one uses refined principal symbols in Sm/Sm-2, which for classical operators correspond simply to the principal plus the subprincipal symbol, and can generally be regarded as the first two terms of its Weyl symbol expansion: we call it the principal Weyl symbol of the pseudodifferential operator. Particular unitary Fourier integral operators, associated to the graph of the canonical transformation, have to be used in the conjugation for the higher accuracy to hold, leading to microlocal representations by oscillatory integrals with specific symbols that are given explicitly in terms of the generating function that locally describes the graph of the transformation. The motivation for the result is based on the optimal symplectic invariance properties of the Weyl correspondence in Rn and its symmetry for real symbols.},

author = {Silva, Jorge Drumond},

journal = {Publicacions Matemàtiques},

keywords = {Operadores pseudodiferenciales; Símbolos; Operadores integrales; pseudo-differential operator; Fourier integral operator; canonical transformation},

language = {eng},

number = {1},

pages = {77-120},

title = {An accuracy improvement in Egorov's theorem.},

url = {http://eudml.org/doc/41888},

volume = {51},

year = {2007},

}

TY - JOUR

AU - Silva, Jorge Drumond

TI - An accuracy improvement in Egorov's theorem.

JO - Publicacions Matemàtiques

PY - 2007

VL - 51

IS - 1

SP - 77

EP - 120

AB - We prove that the theorem of Egorov, on the canonical transformation of symbols of pseudodifferential operators conjugated by Fourier integral operators, can be sharpened. The main result is that the statement of Egorov's theorem remains true if, instead of just considering the principal symbols in Sm/Sm-1 for the pseudodifferential operators, one uses refined principal symbols in Sm/Sm-2, which for classical operators correspond simply to the principal plus the subprincipal symbol, and can generally be regarded as the first two terms of its Weyl symbol expansion: we call it the principal Weyl symbol of the pseudodifferential operator. Particular unitary Fourier integral operators, associated to the graph of the canonical transformation, have to be used in the conjugation for the higher accuracy to hold, leading to microlocal representations by oscillatory integrals with specific symbols that are given explicitly in terms of the generating function that locally describes the graph of the transformation. The motivation for the result is based on the optimal symplectic invariance properties of the Weyl correspondence in Rn and its symmetry for real symbols.

LA - eng

KW - Operadores pseudodiferenciales; Símbolos; Operadores integrales; pseudo-differential operator; Fourier integral operator; canonical transformation

UR - http://eudml.org/doc/41888

ER -

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