#20102 ⟨
a
,
b
|
aab
=
b
,
abba
=
bba
⟩
Up:
Monoid enumeration
Prev:
#20096
⟨
a
,
b
|
aab
=
b
,
abba
=
aaa
⟩
Next:
#20103
⟨
a
,
b
|
aab
=
b
,
abba
=
bbb
⟩
Contents
Properties
Rewriting system
Properties
Sum of relation sides is 11
Infinite non-cancellative non-commutative monoid
Element
a
has infinite order
Not right cancellative, because right multiplication by
b
is not injective:
a
2
⋅
b
=
b
and 1 ⋅
b
=
b
, however
a
2
≠ 1
Rewriting system
Format:
Pretty
Plain
Word:
Enter a word above to compute its normal form. Tips:
Lowercase letters stand for generators.
Spaces are ignored.
Numbers repeat the previous letter, e.g.
b90
.
Strategy:
Leftmost
Rightmost
Result:
1
1
Reduction order:
Left-to-right shortlex with
a
<
b
Certificate
: derivations of all rewriting rules from the defining relations.
#
Rule
Proof
1.
a
2
b
⇒
b
[1]
2.
a
b
2
a
⇒
b
2
a
[2]
3.
a
b
3
⇒
b
3
[3]
# ab:aab=b,abba=bba ab - - aab=b abba=bba abbb=bbb