theorem Th11: :: GOEDELCP:11

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 J being interpretation of Al,A
for v being Element of Valuations_in (Al,A) holds
( J,v |= 'not' (Ex (x,('not' p))) iff J,v |= All (x,p) )