:: deftheorem defines is_a_proof_wrt_IPC INTPRO_2:def 4 :
for X being Subset of MC-wff
for f being FinSequence of [:MC-wff,Proof_Step_Kinds_IPC:] holds
( f is_a_proof_wrt_IPC X iff ( f <> {} & ( for n being Nat st 1 <= n & n <= len f holds
f,n is_a_correct_step_wrt_IPC X ) ) );