Within a constant it's the Laplacian of the function "one over distance"  and is also the charge density of a point charge.  
Within a constant it's the Laplacian of the function "one over distance"  and is also the charge density of a point charge.  Actually an operator which projects out a function's value at the origin, it's not really a function at all.  For ten points, name this mathematical entity, which is zero everywhere except the origin and is designated by a Greek letter.
Within a constant it's the Laplacian of the function "one over distance"  and is also the charge density of a point charge.  
Dirac delta function