A floorplan is a rectangle envelope subdivided by horizontal and vertical line segments into n nonoverlapping basic rectangles, having given dimensions and relative positioning (i.e. topology). This paper presents a formal algebraic specification ( i n SETS notation) appropriate for VLSI physical design layout, and capable of representing both the floorplan topology as well as the modules ' dimensions. The specification proposed allows a concise and rigorous representation of arbitrarily complex composite floorplans. This algebraic description unifies -under a rotation invariant single expression formalism -slicing and non-slicing generalized wheels jloorplans. A s needed b y specific floorplan algorithms, at supports either a topology dimensionless descripiton or the introduction of module dimensions.Finally, it allows a n eightfold reduction -over previous representations -of the total number offlooplan solutions considered in FP algorithms.