Triplication for BSTSs and uncolourability Original Research Article

Characterizing the uncolourable BSTS(v)s is among the problems posed in the book “Triple Systems” (Triple Systems, Clarendon Press, Oxford, 1999.) by Colbourn and Rosa. We investigate the properties of strict colourings of BSTS(3v)s obtained by triplication. In particular, in the case v=9 we answer a question raised in (Strict colourings of STS(3v)s and uncolourable BSTS(3v)s, Submitted.) regarding a class of uncolourable BSTS(27)s.