
Logical Symbols (2011) - pplonski86
http://www.philosophypages.com/lg/e10a.htm
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frabert
It should be noted that these are just _one_ of the ways of expressing the
various connectives.

Among the symbols I've found used:

Conjunction: ∧ ⨉ &

Disjunction: | +

Negation: ¬ ! and "overlining" the terms

Implication: => ⇒ (most common in my experience)

Equivalence: <=> ⇔

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JadeNB
I've never understood why ⊃, rather than ⊂, is used for implication. It has
the disturbing consequence for set theory that "∀x, x ∈ A ⊃ x ∈ B" is the same
statement as "A ⊆ B". I know this goes back at least to Russell and Whitehead,
and probably before. Does anyone know the rationale?

~~~
theoh
There's an answer here:

[https://philosophy.stackexchange.com/questions/23231/is-
ther...](https://philosophy.stackexchange.com/questions/23231/is-there-a-
relationship-between-implication-and-supersets)

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gtf21
These were certainly not the symbols we were taught at university (and that
I've seen in most mathematics texts).

We used:

∧ conjunction

∨ disjunction

⇒ implication

¬ negation

⇔ equivalence (bi-implication)

⊂, ⊃ &c. were for sets.

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carapace
See also "The Markable Mark"
[http://www.markability.net/](http://www.markability.net/)

