Deontic Logic (2006), p. 275
by McNamara, Paul

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Caption

THE DEONTIC OCTODECAGON — PART II

Logic

Aristotelian family

Non-Sigma

Number of labels per vertex (at most)

1

Uniqueness of the vertices up to logical equivalence

Yes

Errors in the diagram

No

Geometry

Shape

Octadecagon (regular)

Colinearity range

0

Coplanarity range

0

Cospatiality range

0

Representation of contradiction

N.A.

Vertex description

Conceptual info

No

Mnemonic support (AEIO, purpurea ...)

No

Form

none

Label type

symbolic

Symbolic field

logic

Contains partial formulas or symbols

No

Logical system

deontic logic

Edge description

Style

Diagram is colored

No

Diagram is embellished

No

Additional notes

OPp is logically equivalent to OP~p.

INp is logically equivalent to IN~p.

SIp is logically equivalent to SI~p.

This diagram is not closed under negation, because it lacks (at least) the negation of OP(~)p.