English
If f has a left inverse for algebraMap R S and f is right-invertible on spectrum S a, then SpectrumRestricts a f holds.
Русский
Если f имеет левую обратную к algebraMap R S и f допустима как правая инверсія на спектре S a, то выполняется SpectrumRestricts a f.
LaTeX
$$$ (\\text{Function.LeftInverse } f (\\mathrm{algebraMap } R S)) \\; \\land\\; (spectrum S a).RightInvOn f (\\mathrm{algebraMap } R S) \\rightarrow \\mathrm{SpectrumRestricts } a f $$$
Lean4
theorem of_rightInvOn (h₁ : Function.LeftInverse f (algebraMap R S))
(h₂ : (spectrum S a).RightInvOn f (algebraMap R S)) : SpectrumRestricts a f
where
rightInvOn x
hx := by
obtain (rfl | hx) := mem_quasispectrum_iff.mp hx
· simpa using h₁ 0
· exact h₂ hx
left_inv := h₁