Beta Assertive Graphs
Ahti Pietarinen, Francesco Bellucci and Daniele Chiffi
Assertive graphs (AGs) modify Peirceâ€™s Alpha part of Existential Graphs (EGs) and are used to reason about assertions without any ad hoc sign of assertion. This paper presents an extension of propositional AGs to Beta by lines. Absence of polarities necessitate Beta-AGs to resort to two kinds of lines: standard lines (a certain method of asserting), and barbed lines (a general method of asserting). A new set of rules of transformations for Beta-AGs is presented that derive theorems of quantificational intuitionistic logic. Beta-AGs offer a new system to analyse assertions through quantificational diagrams.