... class (of signed, gain, or bidirected graphs) Notation: [], [], [B]ã An equivalence class of signed, gain, or bidirected graphs under switching. 27isomorphism (of signed, gain, or bidirected graphs) Notation:=ã ... signing of the underlying graph. Equiva-lent to being additively biased. signed gain graph signed graph with gainsNotation: (Γ,σ,ϕ), (Φ,σ), (,)ã A graph separately gained and signed. signed and ... 13sign of a polygon (in a signed graph) gain of a polygon (in a gain graph)Notation: (C), (C)ã The product of the signs, or gains (taken in the order and direction of an ori-entation of the...