:: deftheorem Def15 defines CnIPC INTPRO_1:def 15 :
for X, b₂ being Subset of MC-wff holds
( b₂ = CnIPC X iff for r being Element of MC-wff holds
( r in b₂ iff for T being Subset of MC-wff st T is IPC_theory & X c= T holds
r in T ) );