Sampling Function
The 1-D sampling function is given by
where
is the Dirac Delta Function. The 2-D version is
which can be weighted to
where
is a reliability weight, 
is a density weight (Weighting Function), and 
is a taper.See also Shah Function, Sinc Function- Archimedes' Recurrence Formula
- Archimedes' Spiral
- Archimedes' Spiral Inverse
- Arc Length
- Arc Minute
- Arcsecant
- Arc Second
- Arcsine
- Arctangent
- Area
- Area Element
- Areal Coordinates
- Area-Preserving Map
- Area Principle
- Arf Invariant
- Argand Diagram
- Argand Plane
- Argoh's Conjecture
- Argument Addition Relation
- Argument (Complex Number)
- Argument (Elliptic Integral)
- Argument (Function)
- Argument Multiplication Relation
- Argument Principle
- Argument Variation