let Al be QC-alphabet ; :: thesis: for A being non empty set
for v being Element of Valuations_in (Al,A)
for S being Element of CQC-Sub-WFF Al holds Val_S (v,S) = Val_S (v,(Sub_not S))
let A be non empty set ; :: thesis: for v being Element of Valuations_in (Al,A)
for S being Element of CQC-Sub-WFF Al holds Val_S (v,S) = Val_S (v,(Sub_not S))
let v be Element of Valuations_in (Al,A); :: thesis: for S being Element of CQC-Sub-WFF Al holds Val_S (v,S) = Val_S (v,(Sub_not S))
let S be Element of CQC-Sub-WFF Al; :: thesis: Val_S (v,S) = Val_S (v,(Sub_not S))
Sub_not S = [('not' (S `1)),(S `2)] by SUBSTUT1:def 20;
hence Val_S (v,S) = Val_S (v,(Sub_not S)) ; :: thesis: verum