fact: Definition CRmax_idem : forall x : CR, CRmax x x == x := @join_idem CRlat.
imports: CoRN.algebra.RSetoid CoRN.metric2.Metric CoRN.metric2.UniformContinuity CoRN.model.partialorder.CRpartialorder CoRN.order.SemiLattice CoRN.order.Lattice