d'Alembert operator

Etymology

Named after Jean le Rond d'Alembert (1717–1783), a French mathematician, mechanician, physicist, philosopher, and music theorist.

Noun

d'Alembert operator (plural d'Alembert operators)

1. (physics) A differential operator which may be expressed as ${\displaystyle \partial _{\mu }\partial ^{\mu }=\sum _{\mu =0}^{3}{\partial \over \partial x^{\mu }}{\partial \over \partial x_{\mu }}}$; it is the four-dimensional (Minkowski space) equivalent of the three-dimensional Laplace operator.