Basic transfer function question Why is the transfer function from node 2 to 3 $H_{23}=\frac{z^{-1}}{1+az^{-1}}$?
I don't understand the $z^{-1}$ in the numerator.
Considering:

$H_{0, 1} = z^{-1} H_{2, 3} = \frac{z^{-1}}{1 + az^{-1}}$

then:

$H_{2, 3} = \frac{1}{1 + a z^{-1}}$