Post #2387172
2026-05-08 18:15 UTC
@atoponce@fosstodon.org — oh _hell_ yes. The surreal numbers provide a rigorous foundation for differential and integral calculus, and one that makes a lot more sense. In my Cauchy-based undergrad calc courses Dr. Wogahn would all but break a ruler over our wrists if we ever thought of dy'dx as a fraction, but they _are_ a fraction — a ratio of two surreal numbers!
If you dig around you can find a great surreal freshman calculus book written by one of the founders of surreal numbers, and he's made it available for free. I highly recommend it. Thanks to it, I actually understand calculus now, as opposed to just being able to do it.
Replies (2)
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@atoponce@fosstodon.org 2026-05-08 22:23
@rob@social.afront.org Thanks! Who is the author of the book by chance?
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@AdrianRiskin@kolektiva.social 2026-05-09 00:03
@rob@social.afront.org @atoponce@fosstodon.org Keisler uses Abraham Robinson's hyperreals, a proper subfield of the surreals, that rigorously model 17th century thinking about infinitesimals. A great book either way, of course!