Specialized Block-Colourings of Steiner Triple Systems and the Upper Chromatic Index

Abstract.Specialized block-colourings of Steiner triple systems, in which the blocks incident at each point have a restricted colour pattern, are examined. Valid block-colourings, in which every element is incident to at least two blocks of the same colour, and to at least two blocks of different colours, are shown to exist for all admissible orders and numbers of colours.