Aristotelian Logic (1991), p. 169
by Parry, William T.; Hacker, Edward A.

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Logic

Aristotelian family

Sigma-0 Graph

Boolean complexity

1

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 ...)

Yes

Form

none

Label type

symbolic

Symbolic field

logic

Contains partial formulas or symbols

Yes

Logical system

syllogistics

Edge description

Contains definitions of relations

No

Form

solid lines

Has arrowheads

Yes

Overlap

No

Curved

No

Hooked

No

As wide as vertices

No

Contains text

No

Label type

none

Style

Diagram is colored

No

Diagram is embellished

No

Tags

Boolean closed

;

non-contingent formulas

Additional notes

The assumption here is that subject and predicate term are identical. Ass and Iss are tautological (under the assumption of existential import), while Ess and Oss are contradictory (under that same assumption). Hence this diagram contains only non-contingent formulas, and is thus a sigma-0 diagram.