Theorem
mtani
≪
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theorem mtani (a b c: wff): $ ~b $ > $ a /\ c -> b $ > $ a -> ~c $;
Step
Hyp
Ref
Expression
1
hyp h1
~b
2
1
a1i
a -> ~b
3
hyp h2
a /\ c -> b
4
2
,
3
mtand
a -> ~c
Axiom use
axs_prop_calc
(
ax_1
,
ax_2
,
ax_3
,
ax_mp
)