let A be non empty set ; :: thesis: for L being lower-bounded LATTICE
for T being T-Sequence
for O being Ordinal
for d being BiFunction of A,L
for q being QuadrSeq of d st O <> {} & O is limit_ordinal & dom T = O & ( for O1 being Ordinal st O1 in O holds
T . O1 = ConsecutiveDelta q,O1 ) holds
ConsecutiveDelta q,O = union (rng T)

let L be lower-bounded LATTICE; :: thesis: for T being T-Sequence
for O being Ordinal
for d being BiFunction of A,L
for q being QuadrSeq of d st O <> {} & O is limit_ordinal & dom T = O & ( for O1 being Ordinal st O1 in O holds
T . O1 = ConsecutiveDelta q,O1 ) holds
ConsecutiveDelta q,O = union (rng T)

let T be T-Sequence; :: thesis: for O being Ordinal
for d being BiFunction of A,L
for q being QuadrSeq of d st O <> {} & O is limit_ordinal & dom T = O & ( for O1 being Ordinal st O1 in O holds
T . O1 = ConsecutiveDelta q,O1 ) holds
ConsecutiveDelta q,O = union (rng T)

let O be Ordinal; :: thesis: for d being BiFunction of A,L
for q being QuadrSeq of d st O <> {} & O is limit_ordinal & dom T = O & ( for O1 being Ordinal st O1 in O holds
T . O1 = ConsecutiveDelta q,O1 ) holds
ConsecutiveDelta q,O = union (rng T)

let d be BiFunction of A,L; :: thesis: for q being QuadrSeq of d st O <> {} & O is limit_ordinal & dom T = O & ( for O1 being Ordinal st O1 in O holds
T . O1 = ConsecutiveDelta q,O1 ) holds
ConsecutiveDelta q,O = union (rng T)

let q be QuadrSeq of d; :: thesis: ( O <> {} & O is limit_ordinal & dom T = O & ( for O1 being Ordinal st O1 in O holds
T . O1 = ConsecutiveDelta q,O1 ) implies ConsecutiveDelta q,O = union (rng T) )

deffunc H1( Ordinal, set ) -> BiFunction of (new_set (ConsecutiveSet A,$1)),L = new_bi_fun (BiFun $2,(ConsecutiveSet A,$1),L),(Quadr q,$1);
deffunc H2( Ordinal, T-Sequence) -> set = union (rng $2);
deffunc H3( Ordinal) -> set = ConsecutiveDelta q,$1;
assume that
A1: ( O <> {} & O is limit_ordinal ) and
A2: dom T = O and
A3: for O1 being Ordinal st O1 in O holds
T . O1 = H3(O1) ; :: thesis: ConsecutiveDelta q,O = union (rng T)
A4: for O being Ordinal
for It being set holds
( It = H3(O) iff ex L0 being T-Sequence st
( It = last L0 & dom L0 = succ O & L0 . {} = d & ( 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 <> {} & C is limit_ordinal holds
L0 . C = H2(C,L0 | C) ) ) ) by Def17;
thus H3(O) = H2(O,T) from ORDINAL2:sch 10(A4, A1, A2, A3); :: thesis: verum