Finding a $\text C^\infty$ function which is zero just on a given closed set
33734
Every closed subset $E\subseteq \mathbb{R}^n$ is the zero point set of a smooth function
119003
Complement of $c_{0}$ in $\ell^{\infty}$
12402
Showing a function on $[0,1]$ is the zero function
109229
An Example of a Nested Decreasing Sequence of Bounded Closed Sets with Empty Intersection
130748
Infinitely differentiable function with given zero set?
55995
Why is the supremum of the empty set $-\infty$ and the infimum $\infty$?
23186
$f: \mathbb{R^2} \to \mathbb{R}$ a $C^\infty$ function such that $f(x,0)=f(0,y)=0$ then exists $g$ such that $f(x,y)=xy\, g(x,y)$
79490
Proving the set of points at which a function diverges to $\infty$ is countable
22210
Points of discontinuity of a bijective function $f:\mathbb{R} \to [0,\infty)$
37736
How to find a function in $ L_{2}(0,\infty)$ but not $L_{q}(0,\infty)$, $q\neq 2 $
124463
Integral from $0$ to $\infty$ of $\ln(x)/e^x$
137883
Cardinality of the set of all (real) discontinuous functions
38695
Inverse of Strictly Monotone Function
132382
Showing a set is nowhere dense in $C([0,1])$
21269
Bijective continuous function between $(0 ,\infty)$ and $\mathbb{R}$.
27675
Polynomials vanishing on an infinite set
140978
Real domain and range function to find all functions with nonzero x.