CS486 Spring 1997

Lecture 12 Thursday, Feb. 27, 1997
Discuss Prelim options: March 13 or 27.

Church's Theorem: first-order validity is undecidable

specifying a Turing machine
halts iff Halt is valid
Post's correspondence problem and validity (see Manna handout)

Sketch of Godël's Completeness Theorem

recall propositional case
define systematic tableau
open counter-example
no counter example closed
valid provable

More hints for ``Class Theorem'': Tableau Proof Refinement Proof

table of rules
position notation
Intuitionistic rule
quantifier rules
case of the theorem,

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