"indeed simple" is correct and usable in written English.
You can use this phrase to emphasize your point or to express agreement. For example, "The instructions were indeed simple, so everyone understood how to use the app."
This principle is indeed simple; however, it is frequently ignored.
Indeed, simple plumbing repairs can fix the faulty flow of international transactions and stop the leakage so that more money can end up where it's needed the most – in the pockets of the world's poorest people.
Indeed, simple examples demonstrate that current aspect compiling techniques do not avoid runtime type errors.
The reason for all these fancy cars sitting idle at the world's biggest mobile phone show is indeed simple: the smartphone market is facing saturation point.
Indeed, simple prion-like transfer mechanisms involving the prion domains of RNA-binding proteins could underlie the classical non-cell-autonomous emanation of neurodegenerative pathology from originating epicenters to neighboring portions of the nervous system.
Indeed, simple difference-in-difference regression estimates reveal that the two sets of policies appear to significantly impact the remitting likelihood of Mexican migrants, as well as their average monthly remittances.
This novella, a version of which appeared in The Paris Review, in 2002, is indeed simpler and sparer than anything else Johnson has written.
Whether it is indeed simpler can be doubted, however, considering the mammoth effort required to supervise many thousands of innocuous reports.
Williams opposes utilitarianism partly for the straightforward reason that it is an "ism",[19] a systematisation often a deliberately brisk or indeed "simple-minded" one (UFA: 149)—of our ethical thinking.
Moreover, the current problem is indeed simpler than the surface wave problem due to the non-slip boundary condition (u|_{partialOmega}=0).
Indeed, simpler methods are often seen as more reliable.
