let H be Element of QC-WFF ; :: thesis: not H is_immediate_constituent_of VERUM
assume A1: H is_immediate_constituent_of VERUM ; :: thesis: contradiction
'not' H is negative by QC_LANG1:def 18;
then A2: ( ((@ VERUM ) . 1) `1 = 0 & ((@ ('not' H)) . 1) `1 = 1 ) by QC_LANG1:49;

now

given H1 being Element of QC-WFF such that A3: ( VERUM = H '&' H1 or VERUM = H1 '&' H ) ; :: thesis: contradiction
( H '&' H1 is conjunctive & H1 '&' H is conjunctive ) by QC_LANG1:def 19;
hence contradiction by A3, QC_LANG1:49; :: thesis: verum

end;

then consider z being bound_QC-variable such that
A4: VERUM = All z,H by A1, A2, Def20;
All z,H is universal by QC_LANG1:def 20;
hence contradiction by A4, QC_LANG1:49; :: thesis: verum