The Syntax of the Logical Language used by the Peirce Alpha Graph Builder

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The syntax of the Alpha part of Peirce's Existential Graphs, i.e. the syntax of its propositional subset, is very simple. There are really only two kinds of entities: atoms and cuts. An atom is a propositional variable indicating some atomic sentence. The proof builder allows all the letters "A" to "Z", not discerning between cases. A cut is, in Peirce's work, a closed line surrounding one or more propositions. With the proof builder, the cut is expressed using brackets. Writing any proposition within brackets indicates that they are enclosed by a cut. Semantically, placing some (simple or complex) proposition within a cut means negating this proposition.

Formally, the formation rules of the language used by the Peirce Proof Puilder (pardon, Builder) are as follows:

Some example propositions


© Christian Gottschall / gottschall@gmx.de / 2012-03-31 01:19:53