In Group theory in a nutshell by A. Zee on pg. 66 he introduces sequences of nested normal subgroups:
$G \rhd H_1 \rhd H_2 \rhd \dots \rhd H_k \rhd I$.
Then he says that this induces a sequence of quotient groups:
$G/ H_1 \supset H_1/H_2 \supset H_2/H_3 \supset \dots \supset H_k$.
Why is this true? And how to interpret this sequence of quotient groups? At first sight it seems strange, as $G/H_1$ consists of cosets of $H_1$ and $H_1/H_2$ consists of cosets of $H_2$, it seems $H_1/H_2$ cannot be a subset of $G/H_1$.
Edit There is an errata available for this statement, it says $H_k$ in the second line should be replaced by $H_{k-1}/H_k$. This doesn't change my question.
It is not true, as pointed out in a comment. What is probably meant is that
Here $H_k/I \cong H_k$, so writing
or
would also be fine.