Set s of identities between relators
(xa) a-1,
(yb) b-1,
(y-1xc) (xyc-1)
cb-1 (yx-1b-1) (yc) (x-1b-1) (x-1yxb-1)
(xc-1) (yxya-1) (yxyxb-1) (yxyxya) (yx2c) (yx2b-1) (yx2ya-1) (ya) (yc) a-1 (x2b-1) (x2yx2yc-1) (x2ya) (x2yc) (xy-1xb-1) (xy-1xya-1) (xy-1a) (xy-1x-1c)