Assertion: principle | /r/HasSubevent | same differential equation
Facets:
value: for the ray path
type: TRANSITIVE-OBJECT
Source sentences:
text: De Witte's treatment is more original than that description might suggest, although limited to two dimensions; it uses calculus of variations to show that Huygens' construction and Fermat's principle lead to the same differential equation for the ray path, and that in the case of Fermat's principle, the converse holds.