 ##  [Eikonal Equation](/eikonal-equation) 

  ##  [Eikonal Equation](https://mathlogic.quantumdictionary.io/eikonal-equation-0) 

  
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- Natural &amp; Formal Sciences -

**Mathematics &amp; Logic Dictionary**

 
Definition

A first-order nonlinear partial differential equation of the form |∇u(x)| = f(x) (commonly |∇T(x)| = 1/c(x)), characterizing the arrival time or phase of a propagating front in a medium by linking the magnitude of the gradient of a scalar field to a spatial speed or slowness.