Just no, and I don't understand what's the point in posting uneducated personal opinions here and stating them as facts.

The "European dark ages" had literally zero progress in algebra, it was Boethius's De arithmetica in the Quadrivium for six centuries until Fibonacci's Liber abaci introduced the hindu-arabic numbers, which he learned in what today we call Algeria. And then algebraic methods (BTW "algorithm" comes from the name of al-Khwarizmi, "algebra" comes from "al-jabr") were unknown in Europe until Robert of Chester translated Khwarizmi's "Hisab Al-jabr w'al-muqabala" to Latin from the original in Arabic. There was zero progress in algebra in Europe for six centuries because they had no algebra. After that (there was a bit of a divide between abacists and algebrists), people doing algebra in Europe used that book until the printed arithmetics/algebras of the 16th century. All of them do mention their sources: you can download them in google books and look it up.

I am not saying they where as important as Carolingian minuscule, but I recall a few things being mentioned in a history of math class 20 years ago.

Really though any progress over 500 years is all it takes to avoid complete stagnation. https://plus.maths.org/content/lost-mathematicians-numbers-n...

PS: Now they where not building the kind of great feats of engineering that gets you geometry progress, but their accounting systems got really complex.

You may want to go do some reading on these topics because pretty much everything you said is incorrect. There was almost no scientific or technological progress during Europe's Early Middle Ages (the so-called "Dark Ages").

https://en.wikipedia.org/wiki/European_science_in_the_Middle...

I mostly agree on science, but technology is a different story. There where real advancements in farming technology resulting in higher crop yields for example. Warfare saw the most obvious improvements but it was not alone.