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Leonardi.DB
a logical geometry project

Structures of Opposition and Comparisons: Boolean and Gradual Cases (2020), p. 134
by Dubois, Didier; Prade, Henri; Rico, Agnès

Caption

Johnson–Keynes octagon

Logic

Aristotelian family
Keynes-Johnson Sigma-4
Boolean complexity
7
Number of labels per vertex (at most)
1
Uniqueness of the vertices up to logical equivalence
Yes
Errors in the diagram
No

Geometry

Shape
Octagon (irregular)
Colinearity range
0
Coplanarity range
0
Cospatiality range
0
Representation of contradiction
By 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
subject negation

Additional notes

An alternative visualization of this diagram occurs on p. 133; cf. here.
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