theorem Th11: :: SUBSTUT2:11

for Al being QC-alphabet
for p being Element of CQC-WFF Al
for x being bound_QC-variable of Al st ( for Sub being CQC_Substitution of Al ex S being Element of CQC-Sub-WFF Al st
( S `1 = p & S `2 = Sub ) ) holds
for Sub being CQC_Substitution of Al ex S being Element of CQC-Sub-WFF Al st
( S `1 = All (x,p) & S `2 = Sub )