From https://www.tensorflow.org/tutorials/representation/word2vec, I just ran into this weird looking "|" bar sign in a formula. What does this "|" mean?
$J_\text{NEG} = \log Q_\theta(D=1 |w_t, h) + k \mathop{\mathbb{E}}_{\tilde w \sim P_\text{noise}} \left[ \log Q_\theta(D = 0 |\tilde w, h) \right]$