@article{Santocanale_2000, title={Free mu-lattices}, volume={7}, url={https://tidsskrift.dk/brics/article/view/20161}, DOI={10.7146/brics.v7i28.20161}, abstractNote={A mu-lattice is a lattice with the property that every unary <br />polynomial has both a least and a greatest fix-point. In this paper<br />we define the quasivariety of mu-lattices and, for a given partially<br />ordered set P, we construct a mu-lattice JP whose elements are<br />equivalence classes of games in a preordered class J (P). We prove<br />that the mu-lattice JP is free over the ordered set P and that the<br />order relation of JP is decidable if the order relation of P is <br />decidable. By means of this characterization of free mu-lattices we<br />infer that the class of complete lattices generates the quasivariety<br />of mu-lattices.<br />Keywords: mu-lattices, free mu-lattices, free lattices, bicompletion<br />of categories, models of computation, least and greatest fix-points,<br />mu-calculus, Rabin chain games.}, number={28}, journal={BRICS Report Series}, author={Santocanale, Luigi}, year={2000}, month={Oct.} }