let r be Sequence of REAL ; for y being Surreal-Sequence
for s being uSurreal-Sequence
for A being Ordinal st s,y,r simplest_up_to A & A c= succ (dom y) holds
s | A is one-to-one
let y be Surreal-Sequence; for s being uSurreal-Sequence
for A being Ordinal st s,y,r simplest_up_to A & A c= succ (dom y) holds
s | A is one-to-one
let s be uSurreal-Sequence; for A being Ordinal st s,y,r simplest_up_to A & A c= succ (dom y) holds
s | A is one-to-one
let A be Ordinal; ( s,y,r simplest_up_to A & A c= succ (dom y) implies s | A is one-to-one )
assume A1:
( s,y,r simplest_up_to A & A c= succ (dom y) )
; s | A is one-to-one
A2:
for a, b being Ordinal st a in b & b in dom (s | A) holds
(s | A) . a <> (s | A) . b
proof
let a,
b be
Ordinal;
( a in b & b in dom (s | A) implies (s | A) . a <> (s | A) . b )
assume A3:
(
a in b &
b in dom (s | A) )
;
(s | A) . a <> (s | A) . b
A4:
(
b in A &
b in dom s )
by A3, RELAT_1:57;
then
a in dom s
by A3, ORDINAL1:10;
then
(
s . b in rng s &
s . a in rng s )
by A4, FUNCT_1:def 3;
then reconsider sb =
s . b,
sa =
s . a as
uSurreal by SURREALO:def 12;
A5:
(
sa = (s | A) . a &
sb = (s | A) . b )
by A3, FUNCT_1:47, ORDINAL1:10;
A6:
succ a c= b
by A3, ORDINAL1:21;
s,
y,
r simplest_on_position b
by A1, A3;
then
sb in_meets_terms s,
y,
r,
b
;
then A7:
sb in_meets_terms s,
y,
r,
succ a
by A6;
b c= dom y
by A1, A4, ORDINAL1:22;
then
y . a in rng y
by A3, FUNCT_1:def 3;
then reconsider ya =
y . a as
Surreal by SURREAL0:def 16;
sb is
sa,
ya,
r . a _term
by A7, ORDINAL1:6;
then A8:
not
sb + (- sa) == 0_No
;
not
sb == sa
hence
(s | A) . a <> (s | A) . b
by A5;
verum
end;
for x1, x2 being object st x1 in dom (s | A) & x2 in dom (s | A) & (s | A) . x1 = (s | A) . x2 holds
x1 = x2
hence
s | A is one-to-one
by FUNCT_1:def 4; verum