On true empty category

According to Chomsky (1981, 1986), empty categories consist of PRO, pro, trace, and variable. However, some empty object positions seem to be incompatible with extant empty categories. Given this, Li (2007a, 2007b, 2014) and Li & Wei (2014) raise the true empty category hypothesis, which holds that true empty category is only an empty position with category and Case features. As a last resort option, it is used mainly to meet the subcatgorization of a verb. This assumption is ingenious, and if proved to be true, it will exert a great impact on the study of UG. In this paper, we evaluate their evidence from topicalization and demonstrate that it can be accounted for without invoking true empty category.