<cite>Yang et al. (2018)</cite> also argued that rank(A ) is as high as vocabulary size V based on the following two assumptions: 1. Natural language is highly context-dependent. In addition, since we can imagine many kinds of contexts, it is difficult to assume a basis that represents a conditional probability distribution for any contexts. 2. Since we also have many kinds of semantic meanings, it is difficult to assume basic meanings that can create all other semantic meanings by such simple operations as addition and subtraction; compressing V is difficult. In summary, <cite>Yang et al. (2018)</cite> indicated that D h N is much smaller than rank(A) because its scale is usually 10 2 and vocabulary size V is at least 10 4 .