Eckhard Bick - VISL

alternative readings cannot be removed without being target directly. For the
Portuguese grammar, in particular, it is important that REMOVE rules allow the
simultaneous management of different kinds of “syntactic” (@-) tags (word
function, clause function, valency instantiation) that are to survive in varying and
multiple combinations), a feature that is inherently relevant for the progressive
level approach.
• Rule complexity, measured by number of context conditions and the percentage of
rules with unbounded contexts, is higher for syntax than for morphology/PoS.
Thus, an average of 3.37 contexts was needed for morphological disambiguation,
4.22 for syntactic mapping and 5.28 for syntactic disambiguation. The proportion
of rules with unbounded contexts and rules with only local contexts (the ones that
could be expressed by HMM taggers) is 10 times higher for syntactic than for
morphological rules (the numbers being 2.0 and 0.2, respectively).
• CG rules are “left-leaning” in the sense that left hand context conditions are more
common in rules than right hand contexts, reflecting the linear and sequential
composition of language. Thus, on all levels and for both absolute and unbounded
contexts, the percentage of left contexts is about 60% (i.e. 40% for right hand
contexts), as opposed to 81% left contexts for unbounded and 42.6% for absolute
contexts in ENGCG (Karlsson, 1995, p. 352).
With its specific focus on Portuguese Dependency Grammar, and its notational
distinction between form (N-, V-, S-, P-tags etc. as well as attachment markers) and
function (@-tags), PALAVRAS represents not only a technical parsing solution, but
also a comprehensive description of Portuguese morphology and syntax. The parser
and its notational system have constantly been tested on authentic corpora ensuring
that no large area of Portuguese syntax remained unconfronted.
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