Fig. 2
From: A unified approach to inferring chemical compounds with the desired aqueous solubility
a Representation of the chemical compound 3-(3-Ethylcyclopentyl) propanoic acid with CID = 20849290 as a chemical graph \({\mathbb {C}}\); b The vertices and edges of the interior and exterior parts of \({\mathbb {C}}\) depicted with black and gray colors, respectively, in the two-layered model. The sets of interior and exterior vertices are \(\{u_1, u_2, \ldots , u_7\}\) and \(\{w_1, w_2, \ldots , w_5\}\), respectively