for Al being QC-alphabet
for p being Element of CQC-WFF Al
for x being bound_QC-variable of Al
for A being non empty set
for vS1 being Val_Sub of A,Al st ( for y being bound_QC-variable of Al st y in dom vS1 holds
not y in still_not-bound_in (All (x,p)) ) holds
for y being bound_QC-variable of Al st y in (dom vS1) \ {x} holds
not y in still_not-bound_in p