For every amount of lookahead k, we can construct examples that cannot be modeled with a locally normalized model by duplicating the middle input b in (7) k + 1 times.
only a local model with scores ρ that considers the entire input can capture any distribution p(d 1:n |x 1:n ): in this case the decompo- increasing the amount of context used as input comes at a cost, requiring more powerful learning algorithms, and potentially more training data.