# `independent_joint`
$$
p(a, b \mid c) = p(a \mid c) p(b \mid c)
$$
Log
$$
\log{p(a, b \mid c)} = \log{p(a \mid c)} + \log{p(b \mid c)}
$$
Log Value Difference
$$
\frac{\partial \log{p(a, b \mid c)}}{\partial (a, b)}
=\left( \frac{\partial \log{p(a \mid c)}}{\partial a} + \frac{\partial \log{p(b \mid c)}}{\partial a}, \, \frac{\partial \log{p(a \mid c)}}{\partial b} + \frac{\partial \log{p(b \mid c)}}{\partial b} \right) \\
=\left( \frac{\partial \log{p(a \mid c)}}{\partial a} + 0 , \, \frac{\partial \log{p(b \mid c)}}{\partial b} + 0 \right) \\
=\left( \frac{\partial \log{p(a \mid c)}}{\partial a}, \, \frac{\partial \log{p(b \mid c)}}{\partial b} \right)
$$
Log Condition Difference
$$
\frac{\partial \log{p(a, b \mid c)}}{\partial c}
=\frac{\partial \log{p(a \mid c)}}{\partial c} + \frac{\partial \log{p(b \mid c)}}{\partial c}
$$