Theorem nfri | index | src |

theorem nfri {x: nat} (a: wff x): $ a -> A. x a $ > $ F/ x a $;
StepHypRefExpression
1 hyp h
a -> A. x a
2 1 ax_gen
A. x (a -> A. x a)
3 2 conv nf
F/ x a

Axiom use

axs_pred_calc (ax_gen)