 and as precondition axioms we have \(\textrm{held-in-hand}(x) \rightarrow \Poss(\mathop{\mathrm{drop}}(x))\) and \(\mathop{\mathrm{broken}}(x) \rightarrow \Poss(\mathop{\mathrm{repair}}(x))\). This action theory is very succinct: one needs only one successor state axiom per fluent and one precondition axiom per action.