Action exclusion axiom
= Action exclusion axiom
{title2=$\neg(a_t\land b_t)$}
A condition forbidding a conflicting pair of action occurrences in one layer. A serial <SATPlan> encoding excludes every distinct pair; parallel encodings exclude the pairs disallowed by their concurrency semantics. Excluding two simultaneous pickups can enforce a one-hand resource restriction even if both individual <precondition> sets hold.