Symbols:U
Universal Set
- $\mathbb U$
Sets are considered to be subsets of some large universal set.
Exactly what this universal set is will vary depending on the subject and context.
When discussing particular sets, it should be made clear just what that universal set is.
However, note that from There Exists No Universal Set, this universal set cannot be everything that there is.
The $\LaTeX$ code for \(\mathbb U\) is \mathbb U .
Open Set
- $U$
Frequently used, and conventionally in many texts, to denote an open set in the context of topology.
The $\LaTeX$ code for \(U\) is U .
Symbol
- $\mathrm {USgal}$
The symbol for the US gallon is $\mathrm {USgal}$.
Its $\LaTeX$ code is \mathrm {USgal} .
Unified Atomic Mass Unit
- $\mathrm u$
The symbol for the unified atomic mass unit is $\mathrm u$.
The $\LaTeX$ code for \(\mathrm u\) is \mathrm u .
Astronomical Unit: Variant
- $\mathrm {ua}$
A symbol for the astronomical unit that was recommended in $2006$ was $\mathrm {ua}$, from the French unité astronomique, but this recommendation was subsequently withdrawn.
The $\LaTeX$ code for \(\mathrm {ua}\) is \mathrm {ua} .