Dirac delta

== English == === Etymology === Named after English theoretical physicist Paul Dirac (1902–1984); the notation was chosen because the symbol behaves analogously to the Kronecker delta. === Noun === Dirac delta (plural Dirac deltas) (mathematics) A function-like symbol denoted as δ, with the property ∫ f ( t ) δ ( x − t ) d t = f ( x ) {\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.