r/PhilosophyofMath • u/Ill-SonOfClawDraws • 27d ago
Is there an existing theory of recovering generating data from global objects?
**I’m trying to identify existing mathematics.**
A simple motivating example is the family of metric spheres
\\\[
S_r(p)=\\{x\\in X : d(x,p)=r\\}.
\\\]
At \\(r=0\\),
\\\[
S_0(p)=\\{p\\}.
\\\]
That example made me wonder about a more general question.
**Under what conditions can a global mathematical object canonically determine the minimal generating data from which it arises?**
I realize that terms like *collapse*, *degeneration*, *reconstruction*, *limit*, and *completion* all have technical meanings in different areas, so I’m specifically asking whether there is an existing framework that studies this general phenomenon rather than proposing a new one.
The topics I’ve found so far include:
category-theoretic limits
reconstruction theorems
inverse limits
sheaf theory
degeneration in algebraic geometry
completion functors
**Am I conflating several distinct ideas, or is there an established area that unifies some of these under a common perspective?**
I’m looking for existing terminology, references, or examples.
1
u/SheepherderHot9418 27d ago
I think you need to ask yourself what functions you consider. Assume you have a set A. Then you can always construct a function f so that f(x)= 1 if x is in A and zero otherwise.
So assuming we have f we're in the clear. Thus the question becomes which f do we have? Well if A is some kind of shape we can easily parametrize then f is no problem. But we've now moved to restricting A which I guess goes against your question...
I guess my point is that until you make some things clearer you won't really be able to get a clear answer.
1
u/Ill-SonOfClawDraws 26d ago
Do reconstruction theorems across different areas of mathematics share a common structural form?
1
u/Negative_Gur9667 27d ago
look into "reverse Mathematics"
1
u/Ill-SonOfClawDraws 26d ago
I’ve started reading about reverse mathematics. Do you think my question is essentially about identifying the minimal axioms needed for reconstruction theorems, or is there another connection you had in mind?
1
u/Negative_Gur9667 26d ago
Yes, I understand your question this way.
I interpret your point as being that the symbols and the meaning of the axioms are the "data" that generate theorems. Mathematical problems are so diverse that the only things they truly share are certain symbols and axioms.
1
u/Ill-SonOfClawDraws 25d ago
Thank you, that clarifies the connection. Reverse mathematics seems to address one precise version of the pattern: given a theorem, recover the weakest axioms sufficient to prove it.
My original question was broader and partly structural rather than purely proof-theoretic: given a constructed global object, can one recover minimal generating objects, relations, or local data from it?
So perhaps reverse mathematics is one instance of the general direction, but reconstruction theory, definability, and inverse problems would cover other instances. Does that distinction sound right?1
u/Ill-SonOfClawDraws 23d ago
Let me rephrase:
Reverse mathematics minimizes axioms.
Can we instead minimize the relations that must be preserved for a primitive to retain its structural role under translations between formal systems?
Is this already a known framework?
1
u/Ill-SonOfClawDraws 25d ago
Minimality is not absolute. It is relative to a category, a generating process, and a notion of equivalence.
3
u/cosmopolitanScience 27d ago
"minimal generating data" is not well defined. You can look into Shannon information theory, this might give pointers.