let B be CQC-WFF-like Element of [:QC-Sub-WFF ,bound_QC-variables :]; :: thesis: for SQ being second_Q_comp of B
for B1 being Element of [:QC-Sub-WFF ,bound_QC-variables :]
for SQ1 being second_Q_comp of B1 st B is quantifiable & B1 is quantifiable & CQCSub_All B,SQ = Sub_All B1,SQ1 holds
( B `2 = B1 `2 & SQ = SQ1 )

let SQ be second_Q_comp of B; :: thesis: for B1 being Element of [:QC-Sub-WFF ,bound_QC-variables :]
for SQ1 being second_Q_comp of B1 st B is quantifiable & B1 is quantifiable & CQCSub_All B,SQ = Sub_All B1,SQ1 holds
( B `2 = B1 `2 & SQ = SQ1 )

let B1 be Element of [:QC-Sub-WFF ,bound_QC-variables :]; :: thesis: for SQ1 being second_Q_comp of B1 st B is quantifiable & B1 is quantifiable & CQCSub_All B,SQ = Sub_All B1,SQ1 holds
( B `2 = B1 `2 & SQ = SQ1 )

let SQ1 be second_Q_comp of B1; :: thesis: ( B is quantifiable & B1 is quantifiable & CQCSub_All B,SQ = Sub_All B1,SQ1 implies ( B `2 = B1 `2 & SQ = SQ1 ) )
assume that
A1: B is quantifiable and
A2: B1 is quantifiable and
A3: CQCSub_All B,SQ = Sub_All B1,SQ1 ; :: thesis: ( B `2 = B1 `2 & SQ = SQ1 )
Sub_All B,SQ = Sub_All B1,SQ1 by A1, A3, Def6;
hence ( B `2 = B1 `2 & SQ = SQ1 ) by A1, A2, Th36; :: thesis: verum