let x be bound_QC-variable; :: thesis: for p being Element of QC-WFF holds
( bound_in (All x,p) = x & the_scope_of (All x,p) = p )
let p be Element of QC-WFF ; :: thesis: ( bound_in (All x,p) = x & the_scope_of (All x,p) = p )
All x,p is universal by QC_LANG1:def 20;
then All x,p = All (bound_in (All x,p)),(the_scope_of (All x,p)) by Th7;
hence ( bound_in (All x,p) = x & the_scope_of (All x,p) = p ) by Th6; :: thesis: verum