D'Alembert operator

English

Etymology

Named after Template:W (1717–1783), a French mathematician, mechanician, physicist, philosopher, and music theorist.

Noun

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

Usage notes

• It may be denoted as ${◻}^2$ (in analogy with the ${\mathrm{\nabla }}^2$ symbol for the Laplacian) or as $◻$ (in analogy with the $\mathrm{\Delta }$ symbol for the Laplacian).
• It may also be denoted as ${\partial }^2$.

Synonyms

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References

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