A funny way to use an MRF
	• The lateral connections form an MRF. • The MRF is used during learning and generation. • The MRF is not used for inference. – This is  a novel idea so vision researchers don’t like it. • The MRF enforces constraints. During inference, constraints do not need to be enforced because the data obeys them. – The constraints only need to be enforced during generation. • Unobserved hidden units cannot enforce constraints. – This requires lateral connections or observed descendants.