#144 ⟨
a
,
b
|
aababab
=1⟩
Up:
Monoids with two generators and one relation
Prev:
#142
⟨
a
,
b
|
aabaabb
=1⟩
Next:
#145
⟨
a
,
b
|
aababba
=1⟩
Quick links
Properties
Rewriting system
Properties
Presentation has sum-of-sides 7
Infinite non-cancellative non-commutative monoid
Not left cancellative, because left multiplication by
a
is not injective:
a
⋅
a
(
ba
)
3
=
a
and
a
⋅ 1 =
a
, however
a
(
ba
)
3
≠ 1
Not right cancellative, because right multiplication by (
ab
)
3
is not injective:
a
(
ba
)
3
⋅ (
ab
)
3
= (
ab
)
3
and 1 ⋅ (
ab
)
3
= (
ab
)
3
, however
a
(
ba
)
3
≠ 1
Enveloping group is isomorphic to ℤ
Rewriting system
Format:
Pretty
Plain
Word to reduce:
Tips:
Lowercase letters stand for generators.
Spaces are ignored.
Numbers repeat the previous letter, e.g.
b90
.
Reduction strategy:
Leftmost
Rightmost
Path to normal form:
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
(
ab
)
3
⇒ 1
[1]
# ab:aababab=1 ab aababab=1