The motivation for developing the lexicon is threefold: firstly, the lexicon is a Dir-w-e-c CBoW PMI Figure 4: Learning curves for the TOEFL, BLESS, and SimLex-999 tests for the three different models (RI-dir-w-e-c, CBoW and PMI) using Wikipedia as data.
an artifact of only using addition for accumulating the distributional vectors in RI is that all vectors will tend towards the dominant eigenvector of the distributional space (this is the case also for standard DSMs built without RI).