Lower and upper chromatic numbers for BSTSs(2 h - 1) ⁄

In [Discrete Math. 174, (1997) 247-259] an infinite class of STSs(2 h i1) was found with the upper chromatic number ¯ ´ = h. We prove that in this class, for all STSs(2 h i 1) with h < 10, the lower chromatic number coincides with the upper chromatic number, i.e. ´ = ¯ ´ = h; and moreover, there exists a infinite sub-class of STSs with ´ = ¯ ´ = h for any value of h.

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