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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. 412
by Kienzler, Wolfgang

Caption

ARISTOTLE rejects subcontrary, does not known <sic> subaltern.

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 ...)
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

Additional notes

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