Decomposition methods for generating algebraic expressions of full square rhomboids and other graphs

The paper investigates relationship between algebraic expressions and two-terminal directed acyclic graphs. We consider rhomboidal non-series-parallel graphs, specifically, a digraph called a full square rhomboid. Our intention is to simplify the expressions of full square rhomboids. We describe two decomposition methods for generating expressions of rhomboidal graphs and carry out their comparative analysis.