Re: Universe nonemptyness assumption and Truth valuations

David C. Ullrich schrieb:

No. For example, the formula

Ax(x=x)

is _not_ a tautology, even though (in the terminology
you use above, which really doesn't seem quite right
to me) it's "true under every truth valuation that is
allowed by those structures".

As far as I can remember, this _is_ a tautology in "Shoenfield".
If fact quite trivialy, as there are logical axioms of the form
t = t
for each Term t.


franz
.

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