let R be Relation; for x being set st x is_minimal_in R & R is connected holds
x is_inferior_of R
let x be set ; ( x is_minimal_in R & R is connected implies x is_inferior_of R )
assume that
A1:
x is_minimal_in R
and
A2:
R is connected
; x is_inferior_of R
thus A3:
x in field R
by A1, Def12; ORDERS_1:def 14 for y being set st y in field R & y <> x holds
[x,y] in R
let y be set ; ( y in field R & y <> x implies [x,y] in R )
assume that
A4:
y in field R
and
A5:
y <> x
; [x,y] in R
R is_connected_in field R
by A2, RELAT_2:def 14;
then
( [x,y] in R or [y,x] in R )
by A3, A4, A5, RELAT_2:def 6;
hence
[x,y] in R
by A1, A4, Def12; verum