We present a transparent condition on a minimal automaton which is equivalent to piecewise testability of the corresponding regular language. The condition simplifies the original Simon’s condition on the minimal automaton in a different way than conditions of Stern and Trahtman. Secondly, we prove that every piecewise testable language L is k-piecewise testable for k equal to the depth of the ...

Abstract A subgroup X of a group G is called transitively normal if in any Y such that $$X\le Y$$ X≤Y and subnormal . Thus all subgroups are only normality transitive relation every (i.e. $$\overline{T}$$ xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:...