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

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

#### Abstract

In [Discrete Math. 174, (1997) 247-259] an infinite class of STSs(2^h-1) was found with the upper chromatic number $\overline{\chi}=h$. We prove that in this class, for all STSs(2^h-1) with h <10, the lower chromatic number coincides with the upper chromatic number, i.e. $\chi=\overline{\chi}=h$; moreover, there exists an infinite sub-class of STSs with $\chi=\overline{\chi}=h$ for any value of h.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11391/920590
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