\[DoubleDownArrow]
• Infix arrow operator.
• x y is by default interpreted as DoubleDownArrow[x, y].
• Extensible character.
• See Section 3.10.4.
• See also: \[DownArrow] , \[DoubleUpArrow] .
Usage
\[DoubleDownArrow] Notes
y is by default interpreted as DoubleDownArrow[x, y]. 
