Example of non complete space
65876
A normed space of continuous functions with norm $\int_{0}^{1}|f(t)|dt$ is not complete
50099
Example of incomplete, but decidable theory, and of complete and undecidable theory, question
18423
Subspace of Lindelöf space is not Lindelöf: Example
160
homeomorphism non-example
70198
Why this two spaces do not homeomorphic?
139988
Counter example for a result of intersection of subspaces
101095
Constructing an example s.t. $\operatorname{Hom}_R(M,N)$ is not finitely generated
65180
A compact Hausdorff space that is not metrizable
55263
Path connected space that is not locally connected
37654
Topology: Example of a compact set but its closure not compact
147961
Characterizing simply connected spaces
63701
An example of a regular function over an open set
106843
Give an example where $\int_{\bar A} f$ exists but $\int_A f$ does not for a continuos $f$ on a bounded open subset $A$ of $\mathbb{R}^n $
79417
A "non-trivial" example of a Cauchy sequence that does not converge?
14516
The space of continuous functions $C([0,1])$ is not complete in the $L^2$ norm
109638
Show that a complete metric space without isolated points is uncountable
124997
finding examples for a non negative and continuous function for which the infinite integral is finite but the limit at infinity doesn't exist