  We follow language theoretic approach to synchronizing automata and
\v{C}ern\'{y}'s conjecture initiated in a series of recent papers. We find a
precise lower bound for the reset complexity of a principal ideal languages.
Also we show a strict connection between principal left ideals and
synchronizing automata. We characterize regular languages whose minimal
deterministic finite automaton is synchronizing and possesses a reset word
belonging to the recognized language.
