We thus implement this constraint in our baseline as a simple post-processing filter on the CRF output.
for probability statement extraction, for a sentence such that |t P | = 0, then we define a modified output y B (B standing here for Baseline) where y B t = O ∀t = 1 : T , else we keep the original output so that y B t = y * t ∀t = 1 : T .