Tony Morris wrote:
You managed to type ∀ but you couldn't find ⊥ ?
OOC, can anybody tell me what ∀ actually means anyway?
It is called the 'universal quantifier' and means "for all". It is often
used implicitly in natural language. e.g. "cars are red" can be expanded
to "[for all elements of the set of cars] cars [all elements of the set]
are red". This statement can be formally expressed (though i won't for now).
The universal quantifier, although most often used implicitly in natural
language, is most often used explicitly in formal logic.
You might also be interested in knowing of the "existential quantifier"
which means "there exists". If I said "there exists a car [an element
from the set of all cars] that is blue", then I have refuted the earlier
logical proposition (that cars are red).
The existential quantifier looks like a backward capital E
∃
Look up "first-order logic" if you're interested in learning more about
this topic.
I see...
I do recall that GHC has some weird extension called "existential
quantification", which makes absolutely no sense at all. So I looked up
the term on Wikipedia, which says "see predicate logic". So I looked up
predicate logic, which says it's an extension of "propositional logic",
so I looked that up... and at this point I became increadibly confused! LOL.
PS: What does OOC stand for? Out Of Curiosity?
Indeed yes.
_______________________________________________
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
