Re: Zermelo-Fraenkel Theory Of Sets

Tony Orlow wrote:
> other. If I say a=b, and a=4, then b=4. if b=6, then a=6. a=b <-> b=a.

No, a=-b <-> b=a just states symmetry of equality.

What you want is phi(a) <-> phi(b).

> Your inability to see equality as anything but a
> unidirectional implication

That was addressed to Darryl. I would bet my life savings (well, my
life savings if I had life savings) that Darryl does not believe that
equality is just unidirectional implication.

MoeBlee

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