Because of this, it is feasible to use discriminative approaches Hosseini et al., 2014;Roy and Roth, 2015;Zhou et al., 2015;Koncel-Kedziorski et al., 2015;Mitra and Baral, 2016) that extract the quantities, featurize the question, and then perform a weighted search over the space of instantiated operator trees or equation templates.
it is not clear how one can extend these discriminative techniques to handle the complex semantics found in Examples 1 and 2.