12
votes
1answer
429 views
Can nonstandard analysis be used to prove results in constructive or computable analysis?
Nonstandard analysis is a useful tool which can be used to prove a number of results in analysis.
Question
Can it also be used to prove results in computable or constructive …
4
votes
1answer
183 views
tennenbaum phenomena for the reals?
Let $\mathfrak{M} = \langle R, +,\times,> \rangle$ be such that $R$ is the set of real numbers and $\mathfrak{M} \models RA^1$ (the first-order axioms for the reals). Do we have ch …
1
vote
0answers
108 views
Integration methods for functions with Delta distributions
Which methods are available for computing a multidimensional integral with Delta distributions (in case one cannot sample them explicitly)?
PS: This question correlates with this …
5
votes
2answers
419 views
Simple example of a sequence without computable modulus of convergence
Can anyone give a simple example of a sequence that converges, but there's no computable function that gives $N$ as a function of $\epsilon$, i.e., the modulus of convergence is no …
11
votes
1answer
320 views
The complexity of the leading fractional bit of a power of a rational number
On a mailing list (math-fun) that I subscribe to Dan Asimov asked what's the most efficient way to calculate the leading decimal digits (say 10 of them) of $(p/q)^n \bmod 1$ where …
10
votes
3answers
912 views
Differentiability of computable functions
Call a computable function a total function $\mathbb{R} \to \mathbb{R}$, for which there exists a Turing machine outputting arbitrary close approximation to $f(x)$ given arbitrary …
1
vote
4answers
411 views
Uncomputability of the identity relation on computable real numbers
Let $f_{=}$ be a function from $\mathbb{R}^{2}$ be defined as follows:
(1) if $x = y$ then $f_{=}(x,y) = 1$;
(2) $f_{x,y} = 0$ otherwise.
I would like to have a proof for / a ref …
2
votes
0answers
246 views
Computable distribution on [0,1] with C-infinity distribution function
Does anyone know of an easily-describable distribution on $[0,1]$ with a density $p$ (with respect to Lebesgue measure) that satisfies the following properties:
$p$ is $C^\infty$ …

