Steiner triple systems with high chromatic index

From a paper with Darryn Bryant, Charlie Colbourn and Daniel Horsley.

In each of the files given below there is an STS as constructed in our paper (with v-2,v-1,v being the infinity points). Each line of the file represents a colour class. Parallel classes are given at the end. In each case the number of parallel classes is the maximum possible for that system, achieving the bound that we prove in our paper.

A 9 colouring of an STS(15)
A 11 colouring of an STS(21)
A 15 colouring of an STS(27)
A 17 colouring of an STS(33)
A 21 colouring of an STS(39)
A 23 colouring of an STS(45)
A 27 colouring of an STS(51)
A 30 colouring of an STS(57)
A 33 colouring of an STS(63)

These colourings, together with bounds proved in the paper, show that for v in {21,33,45} the chromatic index is (v+1)/2, while for v in {15,27,39,51,57,63} the chromatic index is (v+3)/2.

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