let Al be QC-alphabet ; :: thesis: for x being bound_QC-variable of Al
for S being Element of CQC-Sub-WFF Al
for xSQ being second_Q_comp of [S,x] st [S,x] is quantifiable holds
not S_Bound (@ (CQCSub_All ([S,x],xSQ))) in rng (RestrictSub (x,(All (x,(S `1))),xSQ))

let x be bound_QC-variable of Al; :: thesis: for S being Element of CQC-Sub-WFF Al
for xSQ being second_Q_comp of [S,x] st [S,x] is quantifiable holds
not S_Bound (@ (CQCSub_All ([S,x],xSQ))) in rng (RestrictSub (x,(All (x,(S `1))),xSQ))

let S be Element of CQC-Sub-WFF Al; :: thesis: for xSQ being second_Q_comp of [S,x] st [S,x] is quantifiable holds
not S_Bound (@ (CQCSub_All ([S,x],xSQ))) in rng (RestrictSub (x,(All (x,(S `1))),xSQ))

let xSQ be second_Q_comp of [S,x]; :: thesis: ( [S,x] is quantifiable implies not S_Bound (@ (CQCSub_All ([S,x],xSQ))) in rng (RestrictSub (x,(All (x,(S `1))),xSQ)) )
assume A1: [S,x] is quantifiable ; :: thesis: not S_Bound (@ (CQCSub_All ([S,x],xSQ))) in rng (RestrictSub (x,(All (x,(S `1))),xSQ))
then ( x in rng (RestrictSub (x,(All (x,(S `1))),xSQ)) implies not S_Bound (@ (CQCSub_All ([S,x],xSQ))) in rng (RestrictSub (x,(All (x,(S `1))),xSQ)) ) by Th38;
hence not S_Bound (@ (CQCSub_All ([S,x],xSQ))) in rng (RestrictSub (x,(All (x,(S `1))),xSQ)) by A1, Th39; :: thesis: verum