“…Given a set system of individuals and attributes, the MIN-TC problem asks for a minimum subset C of A such that for each pair I, I ′ of I, there is an element C of C such that exactly one of I, I ′ is covered by C, that is, belongs to C (we say that C separates I from I ′ ). The MIN-TC problem appears in a large number of papers under different denominations (minimum test cover ✩ A shorter version of this paper appeared under the name On graph identification problems and the special case of identifying vertices using paths in the Proceedings of the International Workshop on Combinatorial Algorithms, IWOCA 2012 [11]. The present paper contains additional results, mainly Theorems 8, 10 and 20, and a corrected version of Theorems 17 and 18, which contained some mistakes in the short version.…”