Itô is the name of the type of calculus (https://en.wikipedia.org/wiki/It%C3%B4_calculus) and calculare I think is just the plural of calculus. So something like "all the itô calculus are notable examples of fairly high level mathematics ..."
The plural of calculus is calculi or calculuses. Calculare might be an autocorrection for a different language (https://en.wiktionary.org/wiki/calculare), though given that the author has a Korean name, it’s more likely just a weird typo.
That makes so much more sense! Although the pedant in me wants to argue that calculus plural is “calculi”/“calculuses” (the dictionary gives me the latter, although I’ve never seen it in the wild myself—-but I won’t pursue that because it’s beside the point!) Thanks for the help!