Triangle inequality for weird metric
126944
Metric spaces problem
35867
Squaring sides of an inequality
54685
Defining metrics as a function to something other than the reals.
36758
Triangle inequality for L2 norm
116153
The Notorious Triangle Problem
42266
Show that $d(x,y)=\min \{1,|x-y|\}$ is a metric on $\mathbb R$
107321
How to show convexity of a ball in metric space?
50677
Is this metric space incomplete?
98043
How to visualize Reverse Triangle Inequality $||\mathbf{a}| − |\mathbf{b}|| ≤ |\mathbf{a} − \mathbf{b}|$?
105437
How can I show these two metrics give the same topology?
88605
Proof of the Reverse Triangle Inequality
105908
Triangle Inequality for SPD Matrix Norm
99417
An inequality about the sum of distances between points : same color $\le$ different colors?
128786
How to use triangle inequality to establish Reverse triangle inequality
71497
An inequality from Littlewood's Miscellany
26547
Real numbers equipped with the metric $ d (x,y) = | \arctan(x) - \arctan(y)| $ is an incomplete metric space
24975
Weird free spaces estimation