Dirac delta

Named after English theoretical physicist Paul Dirac (1902–1984); the notation was chosen because the symbol behaves analogously to the Kronecker delta.

Dirac delta (plural Dirac deltas)

1. (mathematics) A function-like symbol denoted as δ, with the property ${\displaystyle \int f(t)\delta (x-t)\mathrm {d} t=f(x)}$ , informally understood as a function with an infinite value at 0 and zero elsewhere, and formally as a distribution or a measure.