Uniquely 3-colourable Steiner triple systems

  title={Uniquely 3-colourable Steiner triple systems},
  author={A. D. Forbes},
  journal={J. Comb. Theory, Ser. A},
A Steiner triple system ðSTSðvÞÞ is said to be 3-balanced if every 3-colouring of it is equitable; that is, if the cardinalities of the colour classes differ by at most one. A 3-colouring, f; of an STSðvÞ is unique if there is no other way of 3-colouring the STSðvÞ except possibly by permuting the colours of f:We show that for every admissible vX25; there… CONTINUE READING