theorem :: QC_LANG3:41

for A being QC-alphabet
for p being Element of QC-WFF A
for V being non empty Subset of (QC-variables A) st p is conjunctive holds
Vars (p,V) = (Vars ((the_left_argument_of p),V)) \/ (Vars ((the_right_argument_of p),V)) by Lm2;