Th7:
for f, g being Sequence holds rng (f ^ g) = (rng f) \/ (rng g)
by ORDINAL4:2;
definition
let R be
Relation;
redefine attr R is
transitive means :
Def1:
for
x,
y,
z being
set st
x,
y in R &
y,
z in R holds
x,
z in R;
compatibility
( R is transitive iff for x, y, z being set st x,y in R & y,z in R holds
x,z in R )
compatibility
( R is antisymmetric iff for x, y being set st x,y in R & y,x in R holds
x = y )
end;
theorem Th9:
for
R1,
R2 being
Relation for
x,
y being
set holds
(
x,
y in R1 \, R2 iff (
x,
y in R1 or (
y,
x nin R1 &
x,
y in R2 ) ) )
definition
let X be
set ;
let O be
Operation of
X;
assume A1:
(
O is
co-well_founded &
O is
irreflexive &
O is
finite )
;
existence
ex b1 being Relation of X ex f being Function of X,NAT st
( b1 = value_of f & ( for x being Element of X st x in X holds
ex n being Nat st
( f . x = n & ( x . (iter (O,n)) <> {} or ( n = 0 & x . (iter (O,n)) = {} ) ) & x . (iter (O,(n + 1))) = {} ) ) )
uniqueness
for b1, b2 being Relation of X st ex f being Function of X,NAT st
( b1 = value_of f & ( for x being Element of X st x in X holds
ex n being Nat st
( f . x = n & ( x . (iter (O,n)) <> {} or ( n = 0 & x . (iter (O,n)) = {} ) ) & x . (iter (O,(n + 1))) = {} ) ) ) & ex f being Function of X,NAT st
( b2 = value_of f & ( for x being Element of X st x in X holds
ex n being Nat st
( f . x = n & ( x . (iter (O,n)) <> {} or ( n = 0 & x . (iter (O,n)) = {} ) ) & x . (iter (O,(n + 1))) = {} ) ) ) holds
b1 = b2
end;
definition
let X be
finite set ;
let O be
Operation of
X;
let R be
connected Order of
X;
existence
ex b1 being Relation of X st
for x, y being Element of X holds
( x,y in b1 iff ( x . O <> {} & ( y . O = {} or ( y . O <> {} & (order ((x . O),R)) /. 0,(order ((y . O),R)) /. 0 in R & (order ((x . O),R)) /. 0 <> (order ((y . O),R)) /. 0 ) ) ) )
uniqueness
for b1, b2 being Relation of X st ( for x, y being Element of X holds
( x,y in b1 iff ( x . O <> {} & ( y . O = {} or ( y . O <> {} & (order ((x . O),R)) /. 0,(order ((y . O),R)) /. 0 in R & (order ((x . O),R)) /. 0 <> (order ((y . O),R)) /. 0 ) ) ) ) ) & ( for x, y being Element of X holds
( x,y in b2 iff ( x . O <> {} & ( y . O = {} or ( y . O <> {} & (order ((x . O),R)) /. 0,(order ((y . O),R)) /. 0 in R & (order ((x . O),R)) /. 0 <> (order ((y . O),R)) /. 0 ) ) ) ) ) holds
b1 = b2
end;