let R be Relation; ( R is empty implies ( R is being_quasi-order & R is being_partial-order & R is being_linear-order & R is well-ordering ) )
assume A1:
R is empty
; ( R is being_quasi-order & R is being_partial-order & R is being_linear-order & R is well-ordering )
thus A2:
R is reflexive
ORDERS_1:def 3 ( R is transitive & R is being_partial-order & R is being_linear-order & R is well-ordering )
thus A3:
R is transitive
( R is being_partial-order & R is being_linear-order & R is well-ordering )proof
let x be
set ;
RELAT_2:def 8,
RELAT_2:def 16 for b1, b2 being set holds
( not x in field R or not b1 in field R or not b2 in field R or not [x,b1] in R or not [b1,b2] in R or [x,b2] in R )let y,
z be
set ;
( not x in field R or not y in field R or not z in field R or not [x,y] in R or not [y,z] in R or [x,z] in R )
assume
x in field R
;
( not y in field R or not z in field R or not [x,y] in R or not [y,z] in R or [x,z] in R )
thus
( not
y in field R or not
z in field R or not
[x,y] in R or not
[y,z] in R or
[x,z] in R )
by A1;
verum
end;
hence
( R is reflexive & R is transitive )
by A2; ORDERS_1:def 4 ( R is antisymmetric & R is being_linear-order & R is well-ordering )
thus A4:
R is antisymmetric
( R is being_linear-order & R is well-ordering )
hence
( R is reflexive & R is transitive & R is antisymmetric )
by A2, A3; ORDERS_1:def 5 ( R is connected & R is well-ordering )
thus
R is connected
R is well-ordering
hence
( R is reflexive & R is transitive & R is antisymmetric & R is connected )
by A2, A3, A4; WELLORD1:def 4 R is well_founded
let Y be set ; WELLORD1:def 2 ( not Y c= field R or Y = {} or ex b1 being set st
( b1 in Y & R -Seg b1 misses Y ) )
assume that
A5:
Y c= field R
and
A6:
Y <> {}
; ex b1 being set st
( b1 in Y & R -Seg b1 misses Y )
thus
ex b1 being set st
( b1 in Y & R -Seg b1 misses Y )
by A5, A6, A1; verum