On Mon, Apr 27, 2009 at 11:15 AM, Richard H. McCullough
Syntax is essentially, the process of dealing with forms
of things
and rigourously describing those forms so they can be
recognized by a
parser, or generated by some process.
As I see it, the phrase "formal
syntax" is just a bit redundant,
but maybe it just means that the rigour
used to describe the
forms that expressions/sentences of the language might
match
is important. So while the syntax of the language is
focused
on the way someone might type in or "tell" the computer
some
information, if it is an informal syntax, it might be described
with
generalized terms.
I can imagine an informal syntax for
a language as being
"the words people use to describe the sounds animals
make"
with sentences in that language (for English speakers) being "moo"
"oink", "meow", "ruff", "bow-wow", "neigh", "baa", "whinny", etc.
For non-English speakers, there would be other words, which might
be
interesting to know, and those words would be in this language too.
But
this isn't a FORMAL syntax. Frankly, I don't know if this language
has much
of a formal syntax, it might just be a list of words. (a vocabulary)
I
guess if you say a dog "arfs", you could say it "arfffs" so you could
make
a grammar that has the possibility of multiple "f" characters,
so it could
be possible to describe this language, which I initially
would say is just
requires a vocabulary, to usefully having a grammar,
and thus being able to
be described formally.
Formal semantics is formal first of all, then
semantics after that.
so while a semantics is some kind of meaning, if it
is to be a
formal semantics, then it must have a "form" that is
associated
with it. The form CAN'T be about the way that the
sentences
of the language are defined, because that would be the
syntax
of the language. The form must be something
different.
One possible thing that the formal semantics could be
about,
is that the forms that it deals with would be the forms
that
logical statements could take.
To explain a little more, I can
imagine a logical theory that
had a few predicates like "makesSound" or
"soundsLike", and
then a set of identifiers for animals, and a set of
sentences from
the syntax of the Animal Sounds language mentioned above,
the logical theory would contain logical structures to describe
this
particular aspect of the language. This would be formal
because it
would deal with the FORMs that we could use
(i.e. the shapes that the
extension of the predicates might make),
and it would be semantics, to the
degree that the logic expresses
the "meaning" of which the various
syntactic forms might have.
So to be specific, I imagine there is a
predicate "makesSound"
would establish a link between an element of the
extension of
whatever "Animal" describes, and the sentence in my
Animal
Sounds Langauge. I believe this description constitutes
the
intension of the predicate. Some of the extension of the
set would
be:
makesSound(Dog,"arf")
makesSound(Dog,"bow-wow")
makesSound(Dog,"ruff")
makesSound(Cow,"moo")
makesSound(Pig,"oink")
makesSound(Hog,"oink")
makesSound(Mouse,"eek")
makesSound(Mouse,"eeek")
makesSound(Mouse,"squeek")
I
think this would be expressed in Conceptual Graphs in several ways
I'll try
to use different variants for each of these below: (John Sowa, am I
right?)
[Dog:] -> (makesSound) -> [:"arf"]
[Dog] ->
(makesSound) -> [:"bow-wow"]
(makesSound [Dog:]
[:"ruff"])
[Cow] 1-> (makesSound) 2-> ["moo"]
[Pig] ->
[Hog] -> (makesSound) -> ["oink"]
the other predicate might
be "soundsLike", which links
two Animals or two sounds
together.
soundsLike(Pig,Hog)
soundsLike("arf","ruff")
soundsLike("arf","bow-wow")
I
could even add a rule, making this a logical theory that
could be used for
inferencing:
ForAll S,Q
if (soundsLike(S,Q) AND
(soundsLike(S,R))
then soundsLike(Q,R)
which could be used to
infer
soundsLike("ruff","bow-wow")
This is kind of like a transitive
rule, but I'm not sure if
it technically is, could someone tell me?
By the way, interesting links to follow:
Wordnet (using SUMO's
page) has
http://sigma.ontologyportal.org:4010/sigma/WordNet.jsp?word=animal&POS=1SUMO
has
http://sigma.ontologyportal.org:4010/sigma/Browse.jsp?kb=SUMO&term=Animal