Distance function $\hat{f}(x,y)= |f(x)-f(y)|$
117716
Condition on function $f:\mathbb{R}\rightarrow \mathbb{R}$ so that $(a,b)\mapsto | f(a) - f(b)|$ generates a metric on $\mathbb{R}$
409
functions satisfying $f(x - y) = f(x) f(y) - f(a - x) f(a + y)$ and $f(0)=1$
94218
Showing $d(x,y) = \frac{|x-y|}{1+|x-y|}$ is a distance.
85153
Show that $f(x) = -\ln(x)$ is convex (WITHOUT using second derivative!)
3387
Derivative of $f(x)=|x|$
146318
Derivative of f(x)=arth(lnx)
28822
$|x| - |y| \leq |x-y|?$
137983
Normalisation of $k[x,y]/(y^2-x^2(x-1))$
65827
When $\min_{x \in X,y \in Y} f(x,y) = \min_{x \in X} \min_{y \in Y} f(x,y)$?
20568
Does the following have a solution for f(x,y)?
102672
How to compute the L^2-distance of a given function to the set of Gaussian functions
56958
bounding a $C^1$ function that upholds $f'(t)\leq 1-f(t)^2$
81720
$f(x) + f(x+f(y)) = y + f(f(x) + f(f(y)))$
9924
Derivative of conjugate multivariate function
145439
Function with inputs moved from each other for a distance less than $a$
59063
$f(f(x))=f(x)$ question
11453
Find a real function $f:\mathbb{R}\to\mathbb{R}$ such that $f(f(x)) = -x$?