Re: A Logical Model for Lists as Relations

"vc" <boston103_at_hotmail.com> wrote in message news:1147432647.109675.194350_at_j73g2000cwa.googlegroups.com...
> Jay Dee wrote:
> > vc wrote:
> > > What's an 'operator' ?
> >
> > Something that yields a value. Nilary booleans give false and true,
> > the boolean prefix unary NOT gives the complement of its input, the
> > number infix + give the sum of two operands... Like that. Operator.

> Why don't you revisit your school algebra book ? There, you might
> discover that the operator is just a convenience notation for the
> function.

There are many schools. They can use different vocabulary.

op-er-a-tor (op'uh ray tuhr) n.

1. a person who operates a machine, apparatus, or the like.
2. a person who operates a telephone switchboard.
3. a person who manages an industrial establishment.
4. a person who trades in securities, esp. speculatively or on a large scale.
5. a person who performs a surgical operation; a surgeon.
6. a. a symbol for expressing a mathematical or logical operation.
7. a function, esp. one transforming a function, set, etc., into another. --------> 7. a. a person who accomplishes his or her purposes by cleverness or devious means.
8. a segment of DNA that interacts with a regulatory molecule, preventing transcription of the adjacent region. [1590-1600; < LL]

> > > The 'union on elements' is a beast inconnu in math.
> >
> > How do you describe the comma that appears in {a, b, c}?
> > Punctuation?

> Yes, commas and curly brackets are just readiblity markers
> (punctuation). Have you ever seen a pack of dogs running around with
> curly brackets around them and commas in their midst ? If not, how
> different then is a bunch of dogs from a set of dogs ?

A pack of dogs usually form a relation. Especially when they attack you. And they have commas unless someone eaten them. Received on Thu May 18 2006 - 16:19:42 CEST