We exploit the simplicity of our model to further assimilate external features relevant for answer selection: the inverse sentence frequency (ISF, (Trischler et al., 2016)), the inverse document frequency (IDF) and a modified version of the ISF score which we call local ISF.
we wanted to explore the idea that the first sentence of the document plays a crucial part in generating summaries (Rush et al., 2015;Nallapati et al., 2016).