# Is $\langle\ a,b\ \vert\ aba=bab,\ abab=baba\ \rangle$ a presentation of the free group on a single generator?

Is the following a presentation of the free group generated by a single element?

$\langle\ a,b\ \vert\ aba=bab,\ abab=baba\ \rangle.$

My thinking is the following:

$abab = baba=b(bab)=b^2ab$ by substituting the first relation into the second. Simplifying, we get $a=b$. Since these steps give equivalent statements, the above presentation is in fact $\langle\ a,b\ \vert\ a=b\ \rangle$, ie. the free group on one generator.

Is this correct?

• Yes , What you have said its correct – Chirantan Chowdhury Feb 5 '17 at 18:52