From: neumann@vax.ox.ac.uk
To: GROUP-PUB-FORUM@maths.bath.ac.uk
Date: Sat, 18 Feb 1995 10:40:42 +0000

Dear All, 

Can anyone remind me---or, more likely, tell me---about the group
with presentation  $\langle a, b :  ba = a^2b^2 \rangle$?  It
has obvious infinite cyclic and tetrahedral quotient groups.  Are
there many references to it in the literature?  Tony Crilly has
pointed out to me that Cayley took a side-swipe at it in 1878. 
Rather typically, what Cayley wrote was pretty inconsequential. 
He simply observed that in a non-abelian group generated by two
elements satisfying that relation not every element can be
expressed in the form $a^pb^q$.  

Best wishes, $\Pi$eter Neumann
Queen's: 18.ii.95