Binary Operation
Problem 1
Suppose is a non-empty finite set, and is a binary operation on which is associative i.e. for all. Show that there is an element such that.
X
z
y
x
Î
,
,
X
x
Î
x
x
x
=
o
X
o
(
)
(
)
z
y
x
z
y
x
o
o
o
o
=
Problem 1
X
z
y
x
Î
,
,
X
x
Î
x
x
x
=
o
X
o
(
)
(
)
z
y
x
z
y
x
o
o
o
o
=