The calculation is called simple because it follows directly from the definitions above. Simple means more like "follows directly from definition without fancy math tricks", not " everyone who can read could solve this in 10 minutes".
I think this is also mostly math related, not physics?
Reinforcement learning is a machine learning (ML) technique (“AI” in layman terms) for optimizing neural networks and other types of non-linear models.
As far as ML math goes, this is fairly tame. It looks complicated, but is spelled out clearly in the paper. A lot of these kind of theoretical papers — things that would get published in Automatica — are going to lean very heavy on math.
Source: PhD in Computer Science with dissertation using neural networks.
That's what my son's homework from university looks like. I've done the same stuff about 35 years ago, but as I never used advanced algebra and analysis for my job, I've basically forgotten most of it.
At least I know roughly what my son is talking about. My wife (language teacher of German and English) is completly lost.
I think it says "simple" as due to not discourage the reader, 'cause it's probably a simple substitution in context which just looks complicated at first glance.
[rant] . All authors that often say things like : "we can simply do this or that" ... for me, is dismissive humble bragging. And, if they really wanted to encourage readers they would say : "in the following equation we used substitution" ... something descriptive.
Every time we study a new subject it is always difficult at first and seeing someone bragging, saying it is simple for them, is never encouraging.