Was Lewis Carroll an Amazing Oppositional Geometer? (2014), p. 405
by Moretti, Alessio

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Caption

Jacoby sees the vertices 'Y' and 'U', but not the hexagonal structure.

Logic

Aristotelian family

Jacoby-Sesmat-Blanché Sigma-3

Boolean complexity

3

Number of labels per vertex (at most)

3

Equivalence between (some) labels of the same vertex

No

Analogy between (some) labels of the same vertex

No

Uniqueness of the vertices up to logical equivalence

Yes

Errors in the diagram

No

Geometry

Shape

Triangle (regular)

Colinearity range

1

Coplanarity range

0

Cospatiality range

0

Representation of contradiction

By diametric opposition (but no central symmetry)

Vertex description

Conceptual info

No

Mnemonic support (AEIO, purpurea ...)

Yes

Form

none

Label type

linguistic

,

symbolic

Language

English

Lexical field

syllogistics

Contains partial sentences or single words

No

Contains abbreviations

No

Symbolic field

logic

Contains partial formulas or symbols

Yes

Logical system

syllogistics

Edge description

Style

Diagram is colored

No

Diagram is embellished

No

Tags

Boolean closed

;

existential import