The Medieval Octagon of Opposition for Sentences with Quantified Predicates (2014), p. 366
by Campos Benítez, Juan Manuel

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Logic

Aristotelian family

Sigma-4 Graph

Number of labels per vertex (at most)

2

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

Rectangle (irregular)

Colinearity range

0

Coplanarity range

4

Cospatiality range

0

Representation of contradiction

By some other geometric feature

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

quantification of the predicate

Additional notes

(...) stands for universal quantification

[...] stands for existential quantification

/ stands for negation

The solid lines represent contrariety; the dotted lines represent subcontrariety. There are four contradictory pairs: A/O, A*/O*, N/R and N*/R*. It can be shown that the 16 other pairs of formulas are unconnected.