let p be Element of CQC-WFF ; :: thesis: for x being bound_QC-variable holds
( Ex-bound_in (Ex (x,p)) = x & Ex-the_scope_of (Ex (x,p)) = p )

let x be bound_QC-variable; :: thesis: ( Ex-bound_in (Ex (x,p)) = x & Ex-the_scope_of (Ex (x,p)) = p )
Ex (x,p) is existential by QC_LANG2:def 13;
hence ( Ex-bound_in (Ex (x,p)) = x & Ex-the_scope_of (Ex (x,p)) = p ) by Def4, Def5; :: thesis: verum