  Let $E$ be an elliptic curve defined over a number field with good reduction
at all primes above a fixed odd prime $p$, where at least one of which is a
supersingular prime of $E$. In this paper, we will establish the algebraic
functional equation for the mixed signed Selmer groups of an elliptic curve
with good reduction at every prime above $p$ over a multiple
$\mathbb{Z}_p$-extension.
