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Leonardi.DB
a logical geometry project

Logic. Part I (1921), p. 31
by Johnson, W. E.

Caption

The Square of Independence

Logic

Aristotelian family
Subcontrariety 4-clique
Boolean complexity
4
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
N.A.

Vertex description

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

Edge description

Contains definitions of relations
No
Form
solid lines
Has arrowheads
No
Overlap
No
Curved
No
Hooked
No
As wide as vertices
No
Contains text
No
Label type
linguistic
Language
English
Contains partial sentences or single words
Yes
Contain abbreviations
No

Style

Diagram is colored
No
Diagram is embellished
No

Additional notes

The negation closure of this diagram is a Moretti-Pellissier sigma-4.
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