3 ms·
Logical Symbols (2011)
- frabert 8y agoIt 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: <=> ⇔
- carapace 8y agoSee also "The Markable Mark" http://www.markability.net/ http://www.markability.net/
- JadeNB 8y agoI'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?
- aggerdom 8y agoTaking a wild guess, but I would figure it's about distinguishing statements about truth values and statements about sets. If you think of it as a function, takes in two booleans and returns a booleen. Likewise ⊂ takes a thing and a set and returns a booleen. I've never really been a fan of ⊃, and always personally preferred an arrow.
- theoh 8y agoThere's an answer here: https://philosophy.stackexchange.com/questions/23231/is-there-a-relationship-between-implication-and-supersets https://philosophy.stackexchange.com/questions/23231/is-ther...
- gtf21 8y agoThese 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.