$(\min, \max)$-equivalence of posets and nonnegative Tits forms
We study the relationship between the (min, max)-equivalence of posets and properties of their quadratic Tits form related to nonnegative definiteness. In particular, we prove that the Tits form of a poset S is nonnegative definite if and only if the Tits form of any poset $(\min, \max)$-equivalent to S is weakly nonnegative.
English version (Springer): Ukrainian Mathematical Journal 60 (2008), no. 9, pp 1349-1359.
Citation Example: Bondarenko V. M., Stepochkina M. V. $(\min, \max)$-equivalence of posets and nonnegative Tits forms // Ukr. Mat. Zh. - 2008. - 60, № 9. - pp. 1157–1167.