TY - JOUR AU - Aceto , Luca AU - Fábregas Alfaro, Ignacio AU - Frutos Escrig, David De AU - Ingolfsdottir, Anna AU - Palomino Tarjuelo, Miguel PY - 2011 SN - 2075-2180 UR - https://hdl.handle.net/20.500.14352/43751 T2 - Electronic proceedings in theoretical computer science AB - Covariant-contravariant simulation is a combination of standard (covariant) simulation, its contravariant counterpart and bisimulation. We have previously studied its logical characterization by means of the covariant-contravariant modal logic.... LA - eng M2 - 1 PB - EPTCS TI - Graphical representation of covariant-contravariant modal formulae TY - journal article VL - 64 ER -