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1d
comment Why is Rationals w.r.t addition not an Isomorphism to Rationals w.r.t. multiplication?
In fact, I don't see the link between what you said and I wrote... Can you be more precise in your question?
1d
answered Why is Rationals w.r.t addition not an Isomorphism to Rationals w.r.t. multiplication?
May
20
revised Contracting subsets
added 20 characters in body
May
12
revised Contracting subsets
added 6 characters in body
May
12
comment Contracting subsets
Sure, I edited my question. Thank you.
May
12
revised Contracting subsets
edited body
May
12
asked Contracting subsets
May
4
comment hyperbolic isometry
The unit translation on the real line is just $\mathbb{R} \to \mathbb{R}$, $x \mapsto x+1$.
May
3
answered hyperbolic isometry
May
3
accepted (Un)distorted subgroups in $\mathbb{F}_2 \times \mathbb{F}_2$
May
3
comment (Un)distorted subgroups in $\mathbb{F}_2 \times \mathbb{F}_2$
It is a nice result, thank you!
May
3
answered Find an example of a group morphism
May
1
answered About a relation of non-discernability between (classes of) finitely generated groups.
May
1
answered For groups $A,B,C$, if $A\times B$ and $A\times C$ are isomorphic do we have $B$ isomorphic to $C$?
Apr
30
comment (Un)distorted subgroups in $\mathbb{F}_2 \times \mathbb{F}_2$
@DerekHolt: In fact, I have a sketch of proof that $\langle a,b,cd \rangle$ is an undistorted subgroup, but the argument is really specific to this subgroup, if I change a little the generators, I lose the proof. So I was curious to know whether there exist more "systematic" methods.
Apr
30
comment (Un)distorted subgroups in $\mathbb{F}_2 \times \mathbb{F}_2$
@GregoryGrant: Absolutely.
Apr
30
comment (Un)distorted subgroups in $\mathbb{F}_2 \times \mathbb{F}_2$
In the presentation I give, the group splits as $\langle a,c \rangle \times \langle b,d \rangle$. In the same way, I could write $\mathbb{Z} \times \mathbb{Z} = \langle a,b \mid [a,b]=1 \rangle$.
Apr
30
comment (Un)distorted subgroups in $\mathbb{F}_2 \times \mathbb{F}_2$
Here, $[a,b]=aba^{-1}b^{-1}$ so that $[a,b]=1$ means that $a$ and $b$ commute.
Apr
30
asked (Un)distorted subgroups in $\mathbb{F}_2 \times \mathbb{F}_2$
Apr
19
awarded  Necromancer