In the common use of logic diagrams, the positive term is conveniently located inside the
circle while its negative counterpart is left outside. This practice, already found in Euler's …

Venn diagram system has been extended by introducing names of individuals and their
absence. Absence gives a kind of negation of singular propositions. We have offered here a …

Venn-Peirce diagram system has been extended with the incorporation of individuals and
absence of individuals. Three types of diagram-logic system are presented, and the …

A new diagram system Venn _ i_ o1 Venn io 1 where properties are fundamental and an
object exists only wrt a property is presented. This work modifies both in syntax and …

Spider diagrams represent sets, their cardinalities and, sometimes, the specific individuals
within those sets. They are expressively equivalent to monadic first-order logic with equality …