It is a classical result that $L^p(\Omega) \subset L^q(\Omega)$ when $q<p$ and $|\Omega| < \infty$. I'd like to know if is there an Orlicz version of this fact. In other words, let $L^{G_1}$ and $L^{G_2}$ Orlicz spaces. When we have $L^{G_1} \subset L^{G_2}?$ It seems that this result holds only (maybe) if the Orlicz spaces $L^{G_1} \subset L^{G_2}$ are regular, that is, satisfies the famous $\Delta_2$ and $\nabla_2$ conditions. That is [![enter image description here][1]][1] If you whant to know more about Orlicz Spaces see the beggining of https://arxiv.org/pdf/math/0602388.pdf [1]: https://i.sstatic.net/svWET.png More specifically,Let $G^p$ and $G^q$ regular N-functions with $$ 0<g_0^p \le \frac{t(g_p)'(t)}{g_p(t)} \le g_1^p < \infty $$ and $$ 0<g_0^q \le \frac{t(g_q)'(t)}{g_q(t)} \le g_1^q < \infty $$ Is ther a relation between $g_0^p, g_1^p, g_0^q,g_1^q$ wich imply inclusion between $L^{G^p}$ and $L^{G^q}$? **Obs 1** Notice that $p$ and $q$ above are indexes not powers. **Obs 2$$ I asked this in mathextackexchange withoug answer even when I offered 250 in bounty. I believe now that here is rigth local to ask. Any help is welcome, reference, direct proof etc.