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Using complementary priors to eliminate explaining away

• A “complementary” prior is defined as one that exactly cancels the correlations created by explaining away. So the posterior factors. – Under what conditions do complementary priors exist? – Complementary priors do not exist in general: •  Parameter counting shows that complementary priors cannot exist if the relationship between the hidden variables and the data is defined by a separate conditional probability table for each hidden configuration.

hidden variables

hidden variables

prior

hidden variables

likelihood

data