let s1, s2 be State of S; :: thesis: ( ex f being Function of NAT ,(product the Object-Kind of S) st
( s1 = f . k & f . 0 = s & ( for i being Nat holds f . (i + 1) = Following p,(f . i) ) ) & ex f being Function of NAT ,(product the Object-Kind of S) st
( s2 = f . k & f . 0 = s & ( for i being Nat holds f . (i + 1) = Following p,(f . i) ) ) implies s1 = s2 )
given f1 being Function of NAT ,(product the Object-Kind of S) such that G1: s1 = f1 . k and
G2: f1 . 0 = s and
G3: for i being Nat holds f1 . (i + 1) = H₁(i,f1 . i) ; :: thesis: ( for f being Function of NAT ,(product the Object-Kind of S) holds
( not s2 = f . k or not f . 0 = s or ex i being Nat st not f . (i + 1) = Following p,(f . i) ) or s1 = s2 )
given f2 being Function of NAT ,(product the Object-Kind of S) such that H1: s2 = f2 . k and
H2: f2 . 0 = s and
H3: for i being Nat holds f2 . (i + 1) = H₁(i,f2 . i) ; :: thesis: s1 = s2
f1 = f2 from NAT_1:sch 16(G2, G3, H2, H3);
hence s1 = s2 by G1, H1; :: thesis: verum