Theorem orim1d ≪ | index | src | ≫ 

theorem orim1d (a b c d: wff): $ a -> b -> c $ > $ a -> b \/ d -> c \/ d $;
StepHypRefExpression
1 hyp h 
a -> b -> c
2 idd 
a -> d -> d
3 1, 2 orimd 
a -> b \/ d -> c \/ d

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp)