#2019 ⟨
a
,
b
|
abaaaaab
=
aa
⟩
Up:
Monoids with two generators and one relation
Prev:
#2018
⟨
a
,
b
|
aabbbbba
=
bb
⟩
Next:
#2020
⟨
a
,
b
|
abaaaaab
=
ab
⟩
Quick links
Properties
Rewriting system
Properties
Presentation has sum-of-sides 10
Infinite non-cancellative non-commutative monoid
Not left cancellative, because left multiplication by
a
is not injective:
a
⋅
b
a
5
b
=
a
2
and
a
⋅
a
=
a
2
, however
b
a
5
b
≠
a
Enveloping group: ⟨
a
,
b
|
aaaaaabb
⟩
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
b
<
a
Certificate
: derivations of all rewriting rules from the defining relations.
#
Rule
Proof
1.
ab
a
5
b
⇒
a
2
[1]
2.
a
7
b
⇒
ab
a
6
[2]
# ab:abaaaaab=aa ba abaaaaab=aa aaaaaaab=abaaaaaa