Does the DP-projection dominate the NP or does the latter dominate the determiner system? As of yet this simple question has not received a conclusive answer. While nominal phrases figure prominently in the theory of syntax, the DP- vs. NP-debate remains unresolved, despite the decades-long success of the DP-hypothesis across theoretical frameworks (Szabolcsi 1983, Fukui 1986, Abney 1987 et seq).

Empirically, early arguments in favor of the DP-hypothesis include possessor agreement in Hungarian as well as the possessor –s that can attach to XPs, and gerunds in English. Conceptually, researchers have highlighted parallelisms between sentences and the noun phrase, concluding that like the former, the latter must be introduced and dominated by functional material. Moreover, it has been suggested that noun phrases obtain argument status by virtue of the D-head (Longobardi 1994). Bošković (2008) proposes that the typological split between article-less languages and such with article systems is captured by means of a parameter, correlating with other syntactic properties of the respective languages.

The NP-hypothesis is arguably a minority position in the field as evidenced by the fact that many syntax text books introduce the DP-hypothesis as a standard (e.g. Radford 2004; Adger 2003, Carnie 2013, Koneman & Zeijlstra 2017; Sag, Wasow & Bender 2003 being a notable exception). Several arguments speak in its favor nonetheless and tacit endorsements have recently been expressed from prominent side, based mainly on conceptual grounds (Chomsky 2007: 25-26 and Chomsky, Gallego and Ott 2017).

There is no shortage of data and observations surrounding the debate. We believe that the time is ripe to carefully evaluate the strength of the arguments advanced to buttress one or the other position. Numerous questions require addressing and scrutiny:

• To what extent are noun phrase internal functional categories such as Num, Quant, and indeed D theoretically justified? Can phenomena which have led to their invocation be subsumed under traditional categories like Nouns, pronominals and Adjectives (cf. Jackendoff 1977; van Eynde 2006; Leu 2008, 2015)?
• Are determiners phrasal (Sag, Wasow & Bender 2003; Chomsky 2007: 25-26; Leu 2008)? And what evidence can be advanced for or against the idea? How are they introduced into the structure, by substitution (or descendants thereof) or adjunction (or descendants thereof, cf. Oishi 2015)?
• Since its inception in the 1980s, the DP-hypothesis has contributed to expanding the cross-linguistic descriptive basis and yielded many novel intricate and detailed facts of the structure of nominal phrases (cf. e.g. Alexiadou, Haegeman & Stavrou 2007). So while the hypothesis has doubtlessly helped to deliver insights and unearth many facts, it has been pointed out that "[t]he postulation of Det [… obfuscated] the manifold differences between adjectival and pronominal determiners, and it [… complicated] the treatment of the many properties which the adjectival determiners share with adjectives and which the pronominal determiners share with pronouns"? (van Eynde 2006: 155-156) So categorization of elements within the noun phrase has become more and more fine-grained over the years. And yet: To what extent might theoretically relevant distinctions have been missed?
• Which hypothesis is better equipped to come to terms with properties of "extraction from NP"-phenomena (Bach & Horn 1976: 280; Cattell 1976; Chomsky 1977: 113 ff.; de Kuthy 2002; Davies & Dubinsky 2003; Müller 1995, 2010: 47 ff.; Oishi 2015; Huang 2018)?
• Interestingly, the split between defendants of the NP-hypothesis on the one hand and the DP-hypothesis on the other cross-cuts representatives of different theoretical persuasion. Thus the DP-hypothesis was endorsed within Word Grammar (Hudson 1990), LFG (Bresnan 2001), GB/Minimalism (Chomsky 1986; Alexiadou, Haegeman & Stavrou 2007). At the same time, proponents of the NP-hypothesis, some of who criticized various aspects of the DP-hypothesis, also stem from differing theoretical currents (Sadler & Arnold 1991: 202f., Pollard & Sag 1994: 363–371; Van Langendonck 1994, Chomsky 2007, Bruening 2009, Boeckx 2014). What notions and technical mechanisms are necessary to capture the functional sequence of elements commonly and cross-linguistically preceding the noun if we pursue either the DP-hypothesis or the NP-hypothesis? Which mechanisms are unique to the theoretical setup used? What are the theoretical prices to pay?
• It has been argued that asymmetries between selection of subordinate clauses/C-heads and the ways in which embedding verbs select types of nouns (but not D-heads) call into question a core motivation for the DP-hypothesis (sentence/noun phrase-parallelisms) and thus suggest that the NP-hypothesis – or descendants thereof – is correct, cf. Bruening 2009. Reactions to the argument stress that the argument is inconclusive in that evidence is lacking that verbs syntacticallyselect types (i.e. formal features) of nouns (cf. Salzmann 2018: 23). So while serious damage has been done to the view that verbs select DPs, it has not been shown that they syntactically select NPs (provided syntactic selection is real, cf. Pesetsky 1982 for one opposing view). New pieces of evidence and/or arguments are called for.
• What is the right treatment of classifiers in the languages that have it, e.g. Mandarin Chinese, Japanese, German Sign Language, etc.? And can classifier phenomena inform the DP- vs. NP-debate?
• What is the right treatment of "determiner spread" phenomena, as e.g. Greek, (cf. Alexiadou, Haegeman & Stavrou 2007, Leu 2008)?
• Do the DP- and the NP-hypothesis make different prediction with respect to N(P)-ellipsis phenomena (Corver & van Koppen 2011, Merchant 2014, Murphy to appear)?
• How does the phenomenon of noun incorporation as e.g. in Mohawk (cf. Baker 1988) square with either the NP- or the DP-hypothesis?

As expected with such intricate problems, the issue is both empirical and conceptual. The aim of this workshop is to gather work that speaks to the issue of DP vs. NP, to address questions like – but not limited to – the ones above, to assess the state of the art and to inspire further research. We invite contributions from any formal theoretical framework that advances empirical arguments, be they syntactic, semantic, morphological or phonological. Cross-linguistic aspects are as welcome as evidence from the diachrony of noun phrases. We likewise call for experimental work or language acquisition research that sheds light on the matter.