How to Square Knowledge and Belief (2012), p. 307
by Lenzen, Wolfgang

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Caption

Engel’s (partial) square of opposition

Logic

Aristotelian family

Classical Sigma-2

Boolean complexity

3

Number of labels per vertex (at most)

1

Uniqueness of the vertices up to logical equivalence

Yes

Errors in the diagram

No

Geometry

Shape

Rectangle (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 ...)

No

Form

none

Label type

symbolic

,

generic placeholders

Symbolic field

logic

Contains partial formulas or symbols

No

Logical system

epistemic logic

Edge description

Style

Diagram is colored

No

Diagram is embellished

No