Re: completeness what is it exactly

translogi schrieb:
In propositional logic you are onlu talking about formula's with
constants.
(truth and falsehood)

Most (or even all) axioms are not sentences in this view.

Yes, propositional logic consists only of closed
formulas. All formulas are closed in SAT.

(Lets not consider QSAT, where one can quantify over
propositional variables, i.e. exists p.p, and one
might have prepositional constants and variables.
Example for a constant being f (bottom, _|_))

But there are formuals and schemas, even for propositional
logic.

A formula (small cap):

p -> p

A schema (upper cap):

P -> P

Stands for the following formulas (small cap):

p -> p
q -> q
(p -> q) -> (p -> q)
etc..

Bye
.

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