You're using an ancient browser to surf the modern web. Please update to the latest version (and don't use Internet Explorer!).

Leonardi.DB
a logical geometry project

Was Lewis Carroll an Amazing Oppositional Geometer? (2014), p. 394
by Moretti, Alessio

Caption

Each of the four exterior vertices $\alpha$, $\beta$, $\gamma$ and $\delta$ has its contradictory negation in the middle point of the opposite face.

Logic

Aristotelian family
Non-Sigma
Boolean complexity
4
Number of labels per vertex (at most)
1
Uniqueness of the vertices up to logical equivalence
Yes
Errors in the diagram
No

Geometry

Shape
Tetrahedron (regular)
Colinearity range
0
Coplanarity range
0–1
Cospatiality range
0
Representation of contradiction
N.A.

Vertex description

Conceptual info
No
Mnemonic support (AEIO, purpurea ...)
No
Form
dots
,
none
Label type
symbolic
Symbolic field
logic
Contains partial formulas or symbols
Yes
Logical system
predicate logic

Edge description

Style

Diagram is colored
Yes
Diagram is embellished
No
Tags
existential import

Additional notes

Consider the following partition:
1) A! (all x are y, and there is at least one x)
2) I $\wedge$ O (some x are y and some x are not y)
3) E! (no x are y, and there is at least one x)
4) there are no x

With the bitstrings based on this partition, the formulas of this diagram (in Greek notation) can be represented as follows:

1000 = $ \alpha\beta\delta $
0100 = $ \alpha\beta\gamma $
0010 = $ \alpha\gamma\delta $
0001 = $ \beta\gamma\delta $
1100 = $ \alpha\beta $
1010 = $ \alpha\delta$
1001 = $ \beta\delta $
0110 = $ \alpha\gamma $
0101 = $ \beta\gamma $
0011 = $ \gamma\delta $
1110 = $ \alpha $
1101 = $ \beta $
1011 = $ \delta $
0111 = $ \gamma $

Note: $\alpha\beta$ means $\alpha\wedge\beta$ (cf. p. 391).
↑ Back to top ↑