Re: "Self-Segregating Syntax"?

On Fri, 21 Apr 2006 02:21:57 +0100, And Rosta <and.rosta@...> wrote:
[snip]
>As for the unambiguous parser, the details have naturally changed greatly
>over time, but there are some constants.
>I. I work with a Dependency Grammar model of syntax, in which syntactic
>structure is a tree (without crossing branches) and there is no
>distinction in type between furcating nodes, unary branching nodes and
>terminal nodes. (This is mainly a notational issue, but it makes for
>maximal simplicity & straightforwardness.)
>II. I stick to the principle of no lookahead, which helps to ensure that
>any parsing algorithm is straightforward & unmindboggling.
>III. Not all nodes need be expressed phonologically.
>
>In the antepenultimate incarnation of the syntax, all mothers preceded
>their daughters, and the lexicogrammar specified for each node how many
>daughters it has. This is a variety of your [3a] above.
>
>In the penultimate incarnation of the syntax, mothers could precede or
>follow their daughters. The lexicogrammar specified for each node how
>many daughters it has, and whether it follows its mother or has no
>mother or precedes its mother as first daughter or precedes its mother
>as nonfirst daughter. This is a mixture of your [1] & [3] (but with the
>'length' encoded on what you might call the 'head').
>
>In the current incarnation of the syntax, mothers follow daughters, all
>mothers have exactly two daughters, and mothers form a closed lexical
>class (which happens to be expressed inflectionally). This could be
>classed as your [2] or your [3].
>
>Anyway, it should be clear from the above that the aim is always to
>find an unambiguous algorithm for building a tree without lookahead.
>And the solution always involves a combination of constraints on tree
>shape plus lexicogrammatical information about the combinatorial
>properties of individual nodes. It's easy to find algorithms that work:
>the design challenge is to find the optimal solution (which needs to
>factor in compositional semantics).
>[snip]
Of all replies up 'til this one, this reply is most responsive to the
intent of my original question about how to unambiguously assign a tree to
an utterance.

(Most other techniques offered so far would seem to apply only to a tree of
at most two levels.  While this problem has been mentioned by several
others, nobody else up 'til now, as far as I could tell, had offered a
solution.)

Thank you.

I wish I could see it in operation; also I'd like a little more detail
about the generalities of your techniques you mentioned above.

-----

What is Dependency Grammar, exactly? and what publications describe it
best? and can you detail a little better, perhaps with some examples, why
it helps out on this question?

-----

In Category Grammar, which I understand is "equivalent", somehow, to Tree-
Adjoining Grammar, a member of a non-elementary category is an operator
that intakes a fixed-length list of fixed-position operands, each of a
particular previously-defined category, and outputs a member of some
previously-defined category.

In natlangs, it appears that the most popular positions for the operator
(within the list of operands), are the following:
1. Immediately before the first operand.
2. Immediately after the first operand.
3. Immediately before the last operand.
4. Immediately after the last operand.

Position 1 is "prefix position", also known as "Polish Notation".
Position 4 is "postfix position", also known as "Reverse Polish Notation".
Positions 2 and 3 are "infix position".

Obviously:
if there is only one operand, then
Position 1 = Position 3 and Position 2 = Position 4;
and if there are only two operands, then
Position 2 = Position 3.

Also, unless there are more than three operands, there is no position which
is _not_ on the above list.

-----

The position that the operator takes among its operands, is part of the
definition of the operator-type; as is the number of its operands, and as
are the types of its operands.

It sounds like you're saying that in your conlangs these facts about the
operator-type are always "phonologically coded" into the word for a
particular operator.

Have I understood you?

eldin

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