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Aug 5, 2015 at 8:29 history closed Jeremy Rickard
Andrés E. Caicedo
Chris Godsil
Andy Putman
Alex Degtyarev
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Aug 5, 2015 at 6:04 comment added Terry Tao As for a more computable notion of a limit, you may be interested in the concept of metastability, which I discuss at terrytao.wordpress.com/2007/05/23/…
Aug 5, 2015 at 5:55 comment added Terry Tao However, one can informally interpret "existential" axioms (such as the axiom of choice or the least upper bound axiom) from a "computational" perspective as providing various "oracles" that extend a base computational model. I discuss this (rather non-rigorously) at terrytao.wordpress.com/2010/03/19/…
Aug 5, 2015 at 5:52 comment added Terry Tao Formally, mathematics is founded on axiomatic systems, rather than on computational models; the Church-Turing thesis does not apply to (say) structures of ZFC. In an axiomatic system, a term is well defined so long as it provably has a unique interpretation for all admissible choices of parameters. Computability of this interpretation would be a desirable bonus if available, but is not necessary in order to usefully take advantage of a mathematical definition.
Aug 5, 2015 at 5:49 history edited Daniel Mansfield CC BY-SA 3.0
made title match the updated question
Aug 5, 2015 at 5:37 comment added Daniel Mansfield Thanks for helping me to grow my question. I've split this into two parts: first I'd like to know if there is a decidable version of $\lim$. For the second question I'm interested in people's opinion on what constitutes a definition.
Aug 5, 2015 at 5:27 history edited Daniel Mansfield CC BY-SA 3.0
improved question
Aug 5, 2015 at 4:38 comment added Robert Israel Actually, when you look closely at elementary analysis, lots of things are undecidable. For example, you might consider Richardson's Theorem en.wikipedia.org/wiki/Richardson%27s_theorem which says that, for a very natural class of expressions, it's impossible to tell if they are equal to $0$.
Aug 5, 2015 at 4:03 comment added Noah Schweber Now there is a question, but I don't understand what it means. What would you consider a satisfactory answer?
Aug 5, 2015 at 3:59 history edited Daniel Mansfield CC BY-SA 3.0
made into more of a question
Aug 5, 2015 at 2:04 review Close votes
Aug 5, 2015 at 8:29
Aug 5, 2015 at 1:48 comment added Jeremy Rickard I'm voting to close this as off-topic because MathOverflow is not a discussion forum and this post is seeking to start a discussion rather than asking a question.
Aug 5, 2015 at 1:16 answer added Bjørn Kjos-Hanssen timeline score: 3
Aug 5, 2015 at 0:31 history asked Daniel Mansfield CC BY-SA 3.0