Categories
Tags
Examples-counterexamples
New post in Examples-counterexamples
The homotopy category of complexes
August 1st, 2022
homological-algebra
examples-counterexamples
category-theory
abelian-categories
homotopy-theory
Ring and Subring with different Identities
August 1st, 2022
examples-counterexamples
ring-theory
abstract-algebra
A function not differentiable exactly two points of $[0,1]$. construction of such a function is possible?
August 1st, 2022
examples-counterexamples
derivatives
real-analysis
Composition of nonlinear maps
August 1st, 2022
examples-counterexamples
linear-algebra
Examples of affine schemes
August 1st, 2022
examples-counterexamples
schemes
Is it true that $2^n-1$ is prime whenever $n$ is prime?
August 1st, 2022
elementary-number-theory
prime-numbers
discrete-mathematics
examples-counterexamples
If $g(n) \neq O(f(n))$, is $g(n) = \Omega(f(n))$?
August 1st, 2022
asymptotics
examples-counterexamples
Example of functions that are onto but not one-to-one
August 1st, 2022
functions
elementary-set-theory
examples-counterexamples
Do cubics always have one real root?
March 13th, 2020
polynomials
complex-numbers
roots
examples-counterexamples
real-numbers
Disprove the statement $f(A \cap B) = f(A) \cap f(B)$
August 1st, 2022
functions
elementary-set-theory
examples-counterexamples
Violation of the irrelevant alternative criterion of fairness in a pairwise comparison
April 8th, 2020
examples-counterexamples
voting-theory
Mid-point convexity does not imply convexity
August 1st, 2022
convex-analysis
examples-counterexamples
real-analysis
Prove or disprove: if $R$ and $S$ are two equivalence relations on a set $A$ then $R\cup S$ is also an equivalence relation.
December 25th, 2020
equivalence-relations
discrete-mathematics
solution-verification
examples-counterexamples
relations
Example of quasi-compact, non-quasi seperated scheme where qcqs fails?
August 1st, 2022
algebraic-geometry
examples-counterexamples
Counterexamples for L1-convergence not implying L2-convergence and vice versa
August 1st, 2022
measure-theory
convergence-divergence
examples-counterexamples
lebesgue-integral
functional-analysis
Examples of improper integrals conditionally convergent
August 1st, 2022
examples-counterexamples
improper-integrals
conditional-convergence
Borel-Cantelli Lemma and almost sure convergence
November 6th, 2020
probability-theory
convergence-divergence
examples-counterexamples
borel-cantelli-lemmas
convergence of sequence of averages the other way around
July 26th, 2020
normed-spaces
examples-counterexamples
sequences-and-series
cesaro-summable
Examples of root, parabolic, and borel subgroups corresponding to roots
August 1st, 2022
abstract-algebra
reference-request
examples-counterexamples
root-systems
algebraic-groups
Weak convexity and continuity
August 1st, 2022
convex-analysis
examples-counterexamples
analysis
Infinite abelian group counterexample
August 1st, 2022
group-theory
examples-counterexamples
representation-theory
infinite-groups
Need example for a topological space that isn't connected, but is compact
August 1st, 2022
examples-counterexamples
general-topology
Example of non-differentiable continuous function with all partial derivatives well defined
August 1st, 2022
continuity
multivariable-calculus
derivatives
examples-counterexamples
partial-derivative
Some thinking about the Dini' s Theorem.
August 1st, 2022
examples-counterexamples
real-analysis
Proving that greedy algorithm on TSP does not produce optimal solution
August 1st, 2022
algorithms
graph-theory
examples-counterexamples
Bézier curves: a detailed explanation of how draw a letter
December 29th, 2020
bezier-curve
examples-counterexamples
interpolation
applications
parametrization
Counterexamples to the Matrix norm AM-GM inequality?
August 1st, 2022
examples-counterexamples
matrices
means
normed-spaces
inequality
Locally Compact Hausdorff Space That is Not Normal
August 1st, 2022
examples-counterexamples
general-topology
Example of Something That's Not A Manifold
August 1st, 2022
examples-counterexamples
differential-geometry
manifolds
Why mean independence does not imply independence?
October 8th, 2020
probability-theory
probability
analysis
examples-counterexamples
←
1
2
3
4
5
6
7
8
9
10
…
24
25
→