3 ms·
Infinitesimals and infinities are nice if you're doing some sort of bucketing logic. tiny = infinitesimal huge = infinity N = number to be bucketed
by greggyb 6y ago
Infinitesimals and infinities are nice if you're doing some sort of bucketing logic.
tiny = infinitesimal
huge = infinity
N = number to be bucketed
tiny <= N < 10 --> bucket 1
10 <= N < 20 --> bucket 2
...
X <= N < huge --> last bucket
This removes edge cases you need to test for if you're trying to bucket positive values. This may not be something you've had to do, but I've had reason to want this before on a few occasions.
- karmakaze 6y agoInfinitesimals do not exist in the standard real number system. 'tiny' seems to be more related to the smallest positive representable (normal or subnormal) IEEE 754 float/double type of value which is a real number.
- greggyb 6y agoInfinitesimals tautologically exist in any finite representation of numbers. For floats, it's the smallest representable positive number. For integers of any type, it's 1. As for how common they are, we learn about them in any introductory calculus course when defining derivatives. You come across the idea whenever discussing limits, if somewhat obliquely. If I learned about it in high school math, and again in "real" math courses at my university, I'd say it's pretty standard.
- alisonkisk 6y agoI've never heard of that, and your definition of 1 as infinitesimal is incompatible withbits properties (infinitesimal + infinitesimal + infinitesimal is greater than a non-infinitesimal 2?!) and I don't see a mention on Wikipedia, and it goes against the plain read it of "in-finite-simal". Also, you seem to be conflating "common" with "standard". "standard" is a mathematical term. Infinitesimal are handwavy in standard analysis (epsilon-delta are the rigorous alternative), but exist rigorously in nonstandard analysis. https://en.m.wikipedia.org/wiki/Infinitesimal https://en.m.wikipedia.org/wiki/Infinitesimal
- greggyb 6y agoI guess I'm using the wrong term, then. I often find it useful to have a concept of "smallest representable positive number," specifically for handling edge cases such as the one I gave up-thread. I see how that doesn't map to infinitesimal as defined in the shared link. There are other instances where I've had a need for such a smallest positive number, where logic is simplified as opposed to checking for 0 in a special way. Whether there's an agreed upon term for that, I know where I've found value in programming tasks. When I need such a thing, it is almost invariably in comparisons, so I am not doing arithmetic with multiple instances of that smallest representable positive number.