let L be Lattice; :: thesis: for f being Function of the carrier of L, the carrier of L
for x being Element of L holds (f,0) +. x = x
let f be Function of the carrier of L, the carrier of L; :: thesis: for x being Element of L holds (f,0) +. x = x
let x be Element of L; :: thesis: (f,0) +. x = x
deffunc H₁( Ordinal, set ) -> set = f . $2;
deffunc H₂( Ordinal, Sequence) -> Element of the carrier of L = "\/" ((rng $2),L);
deffunc H₃( Ordinal) -> set = (f,$1) +. x;
A1: for O being Ordinal
for y being object holds
( y = H₃(O) iff ex L0 being Sequence st
( y = last L0 & dom L0 = succ O & L0 . 0 = x & ( for C being Ordinal st succ C in succ O holds
L0 . (succ C) = H₁(C,L0 . C) ) & ( for C being Ordinal st C in succ O & C <> 0 & C is limit_ordinal holds
L0 . C = H₂(C,L0 | C) ) ) ) by Def4;
thus H₃( 0 ) = x from ORDINAL2:sch 8(A1); :: thesis: verum