Lamps in slim rectangular planar semimodular lattices

A planar (upper) semimodular lattice L is slim if the five-element nondistributive modular M3 does not occur among its sublattices. (Planar lattices are finite by definition.) Slim rectangular as particular were defined G. Grätzer and E. Knapp in 2007. In 2009, they also proved that congruence of with at least three elements same those lattices. order to provide an effective tool for studying these lattices, we introduce concept lamps prove several their properties. Lamps tools based on them allow us a new easy way satisfy two previously known Also, use four properties including Two-pendant Four-crown Property Forbidden Marriage Property.