Resumen de Priestley configurations and Heyting varieties
Richard N. Ball, Ales Pultr 
, Jiri Sichler
We investigate Heyting varieties determined by prohibition of systems of configurations in Priestley duals; we characterize the configuration systems yielding such varieties. On the other hand, the question whether a given finitely generated Heyting variety is obtainable by such means is solved for the special case of systems of trees.
