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Leonardi.DB
a logical geometry project

Opposition, Obversion, and Duality (1993), p. 111
by Simons, Peter

Logic

Aristotelian family
Jacoby-Sesmat-Blanché Sigma-3
Boolean complexity
3
Number of labels per vertex (at most)
1
Uniqueness of the vertices up to logical equivalence
Yes
Errors in the diagram
No

Geometry

Shape
Triangle (regular)
Colinearity range
0–1
Coplanarity range
0
Cospatiality range
0
Representation of contradiction
By diametric opposition (but no central symmetry)

Vertex description

Conceptual info
No
Mnemonic support (AEIO, purpurea ...)
Yes
Form
none
Label type
symbolic
Symbolic field
logic
Contains partial formulas or symbols
Yes
Logical system
syllogistics

Edge description

Style

Diagram is colored
No
Diagram is embellished
No
Tags
Boolean closed
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