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Leonardi.DB
a logical geometry project

Quantifiers in Language and Logic (2006), p. 25
by Peters, Stanley; Westerståhl, Dag

Caption

The modern square

Logic

Aristotelian family
Degenerate Sigma-2 with Unconnectedness 4
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
By central symmetry

Vertex description

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

Style

Diagram is colored
No
Diagram is embellished
No
Tags
existential import

Additional notes

In the 'modern' square of opposition, A (and E) lack existential import, so this is a degenerate square.
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