spherical model
...that the critical behaviour of the spherical model in statistical mechanics has been solved for arbitrary real positive dimensions, and is the same for dimensions greater than four?
...that the <a href="./Critical_point_(mathematics)" id="mwBEY" rel="mw:WikiLink" title="Critical point (mathematics)">critical behaviour</a> of the <b id="mwBEc"><a href="./Spherical_model" id="mwBEg" rel="mw:WikiLink" title="Spherical model">spherical model</a></b> in <a href="./Statistical_mechanics" id="mwBEk" rel="mw:WikiLink" title="Statistical mechanics">statistical mechanics</a> has been solved for arbitrary real positive dimensions, and is the same for dimensions greater than four?