Theorem wl-cbvalsbi

Description: Change bounded variables in a special case. The reverse direction seems to involve ax-11 . My hope is that I will in some future be able to prove mo3 with reversed quantifiers not using ax-11 . See also the remark in mo4 , which lead me to this effort. (Contributed by Wolf Lammen, 5-Mar-2024)

	Ref	Expression
Assertion	wl-cbvalsbi	$$⊢\forall x\phi \to \forall y\left[y/x\right]\phi$$

Proof

Step	Hyp	Ref	Expression
1		stdpc4	$$⊢\forall x\phi \to \left[y/x\right]\phi$$
2	1	alrimiv	$$⊢\forall x\phi \to \forall y\left[y/x\right]\phi$$