let z1 be Tuple of 2, BOOLEAN ; :: thesis: ( z1 = <*FALSE *> ^ <*FALSE *> implies Intval z1 = 0 )
assume A1: z1 = <*FALSE *> ^ <*FALSE *> ; :: thesis: Intval z1 = 0
consider k1, k2 being Element of NAT such that
A2: Binary z1 = <*k1,k2*> by FINSEQ_2:120;
A3: z1 = <*FALSE ,FALSE *> by A1, FINSEQ_1:def 9;
then A4: z1 /. 1 = FALSE by FINSEQ_4:26;
A5: z1 /. 2 = FALSE by A3, FINSEQ_4:26;
( 1 in Seg 1 & Seg 1 c= Seg 2 ) by FINSEQ_1:5, FINSEQ_1:7;
then A7: (Binary z1) /. 1 = IFEQ (z1 /. 1),FALSE ,0 ,(2 to_power (1 -' 1)) by BINARITH:def 6
.= 0 by A4, FUNCOP_1:def 8 ;
2 in Seg 2 by FINSEQ_1:5;
then A9: (Binary z1) /. 2 = IFEQ (z1 /. 2),FALSE ,0 ,(2 to_power (2 -' 1)) by BINARITH:def 6
.= 0 by A5, FUNCOP_1:def 8 ;
( (Binary z1) /. 1 = k1 & (Binary z1) /. 2 = k2 ) by A2, FINSEQ_4:26;
then Absval z1 = addnat $$ <*0 ,0 *> by A2, A7, A9, BINARITH:def 7
.= addnat $$ (<*0 *> ^ <*0 *>) by FINSEQ_1:def 9
.= addnat . (addnat $$ <*0 *>),(addnat $$ <*0 *>) by FINSOP_1:6
.= addnat . 0 ,(addnat $$ <*0 *>) by FINSOP_1:12
.= addnat . 0 ,0 by FINSOP_1:12
.= 0 + 0 by BINOP_2:def 23
.= 0 ;
hence Intval z1 = 0 by A5, Def3; :: thesis: verum