There are several aspects of an electronic design that must be captured and expressed by a design interchange format. One of these aspects is the connectivity of the circuit. The circuit connectivity or topology may be defined in several ways: as part of a schematic design@ as an extraction from some layout description@ or as a circuit description in some language such as the input language for a simulator. Connections need to be described between components 'in various views of the circuit. EDIF@ thus@ allows descriptions of circuit connections to be made in several views@ most notably the mask layout@ PCB layout@ symbolic@ schematic@ and netlist views. The netlist view is designed primarily to describe the circuit connections; the layout and schematic views also describe other aspects of the circuit. The way in which the connectivity of a circuit is described is common to all such views.