On laws of the form $ab\equiv ba$ equivalent to the abelian law

Tomaszewski, Witold

Rendiconti del Seminario Matematico della Università di Padova, Tome 136 (2016), pp. 19-34.

N.D. Gupta has proved that groups which satisfy the laws $[x,y]\equiv \left[x{,}_{n}y\right]$ for $n=2,3$ are abelian. Every law $[x,y]\equiv \left[x{,}_{n}y\right]$ can be written in the form $ab\equiv ba$ where $a,b$ belong to a free group $F_2$ of rank two, and the normal closure of $\langle a,b\rangle$ coincides with $F_2$. In this work we investigate laws of this form. In particular, we discuss certain classes of laws and show that the metabelian groups which satisfy them are abelian.