let H be Element of QC-WFF ; :: thesis: ( H is universal implies Subformulae H = (Subformulae (the_scope_of H)) \/ {H} )
assume H is universal ; :: thesis: Subformulae H = (Subformulae (the_scope_of H)) \/ {H}
then H = All ((bound_in H),(the_scope_of H)) by Th7;
hence Subformulae H = (Subformulae (the_scope_of H)) \/ {H} by Th112; :: thesis: verum