DownArrowUpArrow
\[DownArrowUpArrow]
Infix arrow operator. x y is by default interpreted as DownArrowUpArrow[x, y]. Extensible character. See The Mathematica Book: Section 3.10.4. See also: \[UpDownArrow] , \[DoubleUpDownArrow] , \[UpArrowDownArrow] , \[UpEquilibrium] .