Operador unitário

Se ${\displaystyle U\,}$ é normal, então:

• ${\displaystyle \langle Ux,Uy\rangle =\langle x,U^{*}Uy\rangle =\langle x,y\rangle \,}$

• ${\displaystyle U\,U^{*}=I=U^{*}\,U}$ e, portanto, ${\displaystyle U\,}$ é um operador normal.

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