Levy and Goldberg (2014b) proved that when the objective function in Equation (1) is applied to single-word contexts, it is optimized when: where PMI(t, c) = log p(t,c) pα(t)p(c) is the pointwise mutual information between the target word t and the context word c. The analysis presented in Levy and Goldberg (2014b) is valid for every cooccurrence matrix that describes the joint distribution of two random variables.
it can be applied to our case, where the context is not just a single word but an entire sentential context of a target word.