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Leonardi.DB
a logical geometry project

The Logical Square and the Table of Oppositions. Five Puzzles about the Traditional Square of Opposition Solved by Taking up a Hint from Frege (2012), p. 409
by Kienzler, Wolfgang

Logic

Aristotelian family
Classical Sigma-2
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
Square (regular)
Colinearity range
0
Coplanarity range
0
Cospatiality range
0
Representation of contradiction
By some other geometric feature

Vertex description

Conceptual info
No
Mnemonic support (AEIO, purpurea ...)
No
Form
none
Label type
linguistic
Language
English
Lexical field
syllogistics
Contains partial sentences or single words
No
Contains abbreviations
Yes

Edge description

Style

Diagram is colored
No
Diagram is embellished
No
Tags
duality

Additional notes

Contradiction is on the vertical edges, rather than on the diagonals. Subcontrariety and subalternation are not explicitly visualized.
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