Title: Comment on the Equality Condition for the I-MMSE Proof of Entropy Power Inequality,
Abstract: The paper establishes the equality condition in the I-MMSE proof of the
entropy power inequality (EPI). This is done by establishing an exact
expression for the deficit between the two sides of the EPI. Interestingly, a
necessary condition for the equality is established by making a connection to
the famous Cauchy functional equation.