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Mathlib.LinearAlgebra.CliffordAlgebra.Star

Star structure on CliffordAlgebra #

This file defines the "clifford conjugation", equal to reverse (involute x), and assigns it the star notation.

This choice is somewhat non-canonical; a star structure is also possible under reverse alone. However, defining it gives us access to constructions like unitary.

Most results about star can be obtained by unfolding it via CliffordAlgebra.star_def.

Main definitions #

instance CliffordAlgebra.instStarRing {R : Type u_1} [CommRing R] {M : Type u_2} [AddCommGroup M] [Module R M] {Q : QuadraticForm R M} :
Equations
  • One or more equations did not get rendered due to their size.
theorem CliffordAlgebra.star_def {R : Type u_1} [CommRing R] {M : Type u_2} [AddCommGroup M] [Module R M] {Q : QuadraticForm R M} (x : CliffordAlgebra Q) :
star x = CliffordAlgebra.reverse (CliffordAlgebra.involute x)
theorem CliffordAlgebra.star_def' {R : Type u_1} [CommRing R] {M : Type u_2} [AddCommGroup M] [Module R M] {Q : QuadraticForm R M} (x : CliffordAlgebra Q) :
star x = CliffordAlgebra.involute (CliffordAlgebra.reverse x)
@[simp]
theorem CliffordAlgebra.star_ι {R : Type u_1} [CommRing R] {M : Type u_2} [AddCommGroup M] [Module R M] {Q : QuadraticForm R M} (m : M) :
@[simp]
theorem CliffordAlgebra.star_smul {R : Type u_1} [CommRing R] {M : Type u_2} [AddCommGroup M] [Module R M] {Q : QuadraticForm R M} (r : R) (x : CliffordAlgebra Q) :
star (r x) = r star x

Note that this not match the star_smul implied by StarModule; it certainly could if we also conjugated all the scalars, but there appears to be nothing in the literature that advocates doing this.

@[simp]
theorem CliffordAlgebra.star_algebraMap {R : Type u_1} [CommRing R] {M : Type u_2} [AddCommGroup M] [Module R M] {Q : QuadraticForm R M} (r : R) :