Figure 1.

Setup. We consider receptor monomers (top row) that bind ligand 1 (U), ligand 2 (V), or both competitively (W), and their associated dimers (middle row). (Bottom row) The table defines the 16 possible two-input logic gates in terms of binary input and output; below the table, for the four functionally unique gates, we plot the continuous analogs given by the statistical mechanical model.