Let $I$, $J$ be ideals in the commutative Noetherian ring $R$ (with unity) such that $I\subset J$ (strict subset). Must it always be the case that $\operatorname{ht} I < \operatorname{ht} J$ ?
If $I$ and $J$ both are prime ideals, then this is true. But here given $I$ and $J$ any arbitrary ideal of $R$.
Edit: I think I got the answer. Answer will be NO.
Take $R=K[x, y]$ where $K$ is a field. Take Ideal $I= <x^2, xy>$ and $J= \sqrt{I} = <x, y>$, then $\operatorname{ht} I = \operatorname{ht} J$ but $I \subset J$.
Am I correct?