triangle inequality,
n.
1
. the proposition that the sum of any two sides of a triangle is greater than the third.
2
. the requirement that
d
(
x
,
y
) +
d
(
y
,
z
) ≥
d
(
x
,
z
),
(for a binary real-valued function
d
), or that
|
x
| + |
y
| ≥ |
x
+
y
|
See
metric
,
norm
.
