let n be Ordinal; for T being connected TermOrder of n
for b1, b2 being bag of n holds
( min (b1,b2,T) <= b1,T & min (b1,b2,T) <= b2,T )
let T be connected TermOrder of n; for b1, b2 being bag of n holds
( min (b1,b2,T) <= b1,T & min (b1,b2,T) <= b2,T )
let b1, b2 be bag of n; ( min (b1,b2,T) <= b1,T & min (b1,b2,T) <= b2,T )
per cases
( b1 <= b2,T or b2 <= b1,T )
by Lm5;
suppose A2:
b2 <= b1,
T
;
( min (b1,b2,T) <= b1,T & min (b1,b2,T) <= b2,T )now ( ( b1 = b2 & min (b1,b2,T) <= b1,T & min (b1,b2,T) <= b2,T ) or ( b1 <> b2 & min (b1,b2,T) <= b1,T & min (b1,b2,T) <= b2,T ) )per cases
( b1 = b2 or b1 <> b2 )
;
case
b1 <> b2
;
( min (b1,b2,T) <= b1,T & min (b1,b2,T) <= b2,T )then
b2 < b1,
T
by A2;
then
not
b1 <= b2,
T
by Th5;
then
min (
b1,
b2,
T)
= b2
by Def4;
hence
(
min (
b1,
b2,
T)
<= b1,
T &
min (
b1,
b2,
T)
<= b2,
T )
by A2, Lm2;
verum end; end; end; hence
(
min (
b1,
b2,
T)
<= b1,
T &
min (
b1,
b2,
T)
<= b2,
T )
;
verum end; end;