# formal proof

Printable View

• April 2nd 2009, 10:17 AM
andrei
[SOLVED]formal proof
Help me please to find a solution for the last formula in exercise 12.8. from "Introduction to mathematical logic" by A.Church. Here it is:
Quote:

Prove as theorem of $\mathrm{P_{\mathrm{W}}}$ without making use of the fourth axiom $f\supset p$:
$[p\supset r]\supset[[[p\supset q]\supset r]\supset r]$.