This Commentaire bears out a prediction of Anand et al.'s (Reference Anand, Hardt and McCloskeyto appear) syntactic identity condition on sluicing: sluicing is possible where only a small clause predicate has an antecedent.

Drawing on the Santa Cruz sluicing data set (Anand et al. Reference Anand, Hardt and McCloskey2021), Anand et al. (Reference Anand, Hardt and McCloskeyto appear) (henceforth AHM) show that sluicing is possible with small clause (SC) antecedents. See example (1), where modal stands for a modal of vague or ambiguous force or flavor, be reflects the implied presence of a copula, and greyed out text represents ellipsis (AHM):

In (1), the entire small clause is shared between the preceding discourse and the ellipsis site. AHM show further that sluicing is possible where only the subject of an elided small clause has an antecedent. In (2), the antecedent consists only of the nominal a presidential race (which receives an E-type anaphoric interpretation in the ellipsis site). The small clause predicate when, meanwhile, is extracted as the wh-remnant:

AHM argue that sluicing does not require syntactic identity for the whole elided constituent; viz. the appearance of modal and be in (1) and (2), among other possible mismatches that they document in the TP domain in terms of polarity, tense, modality, and finiteness. Rather, sluicing requires syntactic identity over ‘argument domains’ (AHM: 15; see Rudin Reference Rudin2019 for vP). Since small clauses are argument domains, syntactic identity is satisfied in (1). The small clause is again the relevant argument domain in (2). However, elements moved out of the ellipsis site do not require an identical antecedent (a freedom that elsewhere allows for sprouting). Hence the elided small clause subject alone satisfies syntactic identity, based on its nominal antecedent. Per AHM (fn. 17), “A further prediction is that there should be examples in which the subject of the small clause is extracted and in which only the predicate must be matched under ellipsis.”

This prediction is borne out in (3). The small clause subject which items is extracted, with only the small clause predicate buy one get one free finding an antecedent:

The small clause structure assumed in (3), with the wh-remnant as the subject and the pricing offer as the predicate, is supported by the contrast in (4):

The observation of sluicing where only the small clause predicate has an antecedent strengthens the argument that sluicing requires syntactic identity over argument domains. Further examples – both, like (3), involving prices – are given in (5) and (6):