\[UDoubleDot] (Mathematica Character Name)

Unicode: 00FC. Alias: Esc u" Esc. Letter. Included in ISO Latin-1.

\[UGrave] (Mathematica Character Name)

Unicode: 00F9. Alias: Esc u` Esc. Letter. Included in ISO Latin-1.

\[UnderBrace] (Mathematica Character Name)

Unicode: FE38. Alias: Esc u{ Esc. Letter-like form. Extensible character.

\[UnderBracket] (Mathematica Character Name)

Unicode: 23B5. Alias: Esc u[ Esc. Letter-like form. Extensible character.

\[UnderParenthesis] (Mathematica Character Name)

Unicode: FE36. Alias: Esc u( Esc. Letter-like form. Extensible character.

\[UnionPlus] (Mathematica Character Name)

Unicode: 228E. Infix operator. x ⊎ y is by default interpreted as UnionPlus[x,y]. Used to denote union of multisets, in which multiplicities of elements are added.

\[UpArrowDownArrow] (Mathematica Character Name)

Unicode: 21C5. Infix arrow operator. x ⇅ y is by default interpreted as UpArrowDownArrow[x,y]. Extensible character.

\[UpDownArrow] (Mathematica Character Name)

Unicode: 2195. Infix arrow operator. x ↕ y is by default interpreted as UpDownArrow[x,y]. Extensible character.

\[UpEquilibrium] (Mathematica Character Name)

Unicode: 296E. Infix arrow-like operator. x ⥮ y is by default interpreted as UpEquilibrium[x,y]. Extensible character.

\[UpperLeftArrow] (Mathematica Character Name)

Unicode: 2196. Infix arrow operator. x ↖ y is by default interpreted as UpperLeftArrow[x,y]. Extensible character; grows by default to limited size.