When Singular and Plural are Both Grammatical: Semantic and Morphophonological Effects in Agreement.
a b c d d c b a d c b a d c b a Arrows are annotated by the substrucure to which they are applied d c b a Figure 3: Why ?! is weakly Church-Rosser Note that all that was said in this section generalizes beyond CCG derivations to any associative algebra. Given the rightmost subconstituent recovered using the normal form technique above, how should parsing proceed? Obviously, if the leftward looking category which precipitated the normal form computation is a modiier, i.e. of the form XnX, then it ought to be combined with the recovered constituent in a form analogous to Chomsky adjunction. But what if this category is not of the form XnX? For example, should the parser compute the reanalysis in (10)? (10) a/b b/c >1 a/c c/d >1 a/d sn(a/b)n(b/d) a/b b/c c/d >1 b/d sn(a/b)n(b/d) <0 sn(a/b) <0 s Ascribing the same non-garden-path status to the reanalysis in (10) that we do to (6) would constitute a very odd move: Before reanalysis, the derivation encoded the commitment that the /b of the rst category is satissed by the b of the b/c in the second category. This commitment is undone in the reanalysis. This is an undesirable property to have in a computational model of parsing commitment, as it renders certain revisions of commitments easier than others, without any empirical justiication. Furthermore, given the possibility that the parser change its mind about what serves as argument to what, the interpreter must be able to cope with such non-monotonic updates to its view of the analysis so far | this would surely complicate the design of the interpreter. 8 Therefore, constituents on the right-frontier of a right-normal-formshould only combine withèndocentric' categories to their right. The precise deenition ofèndocentric' depends on the semantic formalism used | it certainly includes post-head modiiers, and might also include coordination. Stipulating that certain reanalyses are impossible immediately makes the parserìncomplete' in the sense that it cannot nd the analysis in (10). From the current perspective of identifying garden paths, this incompleteness is a desirable, even a necessary property. In (10), committing to the composition of a/b and b/c is tantamount to being led down the garden path. In a diierent sense, the current parser is complete: it nds all analyses if the Viable Analysis Criterion and the interpreter never discard any analyses. 7 Conclusion The current proposal shifts …