For word w n in document d, instead of sampling z n , x n,1 , x n,2 independently, we sample them as a block as follows: The above three equations can be normalized to form a 2 * K + 1 multinomial distribution: one component for generating a word from the ideology topic, K components for generating the word from the ideology-independent portion of topic k = 1, • • • , K, and finally K components for generating the word from the ideology-specific portion of topic k = 1, • • • , K. Each of these 2 * K + 1 cases corresponds to a unique assignment of the variables z n , x n,1 , x n,2 .
a conservative writer might stress issues like pro-life, God and faith.