Reaching Semilinear Target Sets in Automata with One Counter I will introduce a (novel) generalised reachability problem in automata with one counter with a variety of semantics. The goal of the seminar is to identify what features of target sets make the reachability problem easy or (NP-)hard and to detail some new concepts and algorithmic techniques for one-dimensional integer VASS (and 1-dimensional Parikh automata). About joint work with Yousef Shakiba and Georg Zetzsche. MIMUW Automata Theory Seminar University of Warsaw, Poland Henry Sinclair-Banks, 16/04/25