
Continuous vs Discrete Variables - Mathematics Stack Exchange
Dec 14, 2025 · Both discrete and continuous variables generally do have changing values—and a discrete variable can vary continuously with time. I am quite aware that discrete variables are those …
What is the intuition for semi-continuous functions?
A function is continuous if the preimage of every open set is an open set. (This is the definition in topology and is the "right" definition in some sense.) The definitions you cite of semicontinuities claim …
The graph of a continuous function is a topological manifold
Sep 18, 2024 · That the preimage of every basis element is open is sufficient for the inverse function to be continuous is seen on page 103 of Munkres' second ed. of Topology. I hope this makes your life …
Why is the determinant continuous? - Mathematics Stack Exchange
Here you want to refer to the topology of the latter as a normed space, which does not depend on the norm since they are all equivalent in finite dimension. Then the determinant is a polynomial in the …
real analysis - Prove that every convex function is continuous ...
The authors prove the proposition that every proper convex function defined on a finite-dimensional separated topological linear space is continuous on the interior of its effective domain. You can likely …
real analysis - Are Continuous Functions Always Differentiable ...
Oct 26, 2010 · An interesting fact is that most (i.e. a co-meager set of) continuous functions are nowhere differentiable. The proof is a consequence of the Baire Category theorem and can be found (as an …
Closure of continuous image of closure - Mathematics Stack Exchange
Nov 14, 2012 · Closure of continuous image of closure Ask Question Asked 13 years, 4 months ago Modified 13 years, 4 months ago
Topological properties preserved by continuous maps
You'll find topological properties with indication of whether they are preserved by (various kinds of) continuous maps or not (such as open maps, closed maps, quotient maps, perfect maps, etc.). For …
Why not include as a requirement that all functions must be …
Jun 20, 2018 · We know that differentiable functions must be continuous, so we define the derivative to only be in terms of continuous functions. But then, the fact that differentiable functions are …
integration - Primitive of an $L^1$ function is continuous ...
Oct 31, 2015 · Precisely, a primitive of a continuous map on a compact interval is continuous on the interior of that interval.