Superimposed maps of binding curve line shapes and binding parameter identifiability for three-site binding curves. Binding curves computed for a given (a, b) pair are shown in the corresponding position in the (a, b) parameter space. Numerical values represent, from top to bottom, the asymptotic errors for parameters p₁, a, and b for each binding curve. Values are shown in bold text if the corresponding asymptotic error is ≥5% (indicating that the parameter is PI) and in normal text if the asymptotic error is <5% (indicating that the parameter is not PI). Regions are colored according to parameter PI: yellow if all parameters are PI, light green if a subset of the parameters is PI, and dark green if none of the parameters are PI. Uppercase roman numerals I–IV identify the four quadrants demarcated by the critical values (a_c and b_c) of the shape parameters. Circled binding curves marked A and B indicate example curves A and B referred to in main text.