🌐EnglishEnglishDeutschEspañolFrançaisРусский한국어中文日本語EntityQ1303846· pop 13· linked from 23 articlesEikonal equationnon-linear partial differential equation encountered in problems of wave propagationAvailable in 13 languagesEspañolFrançaisDeutsch中文日本語РусскийCatalanCzechHebrewNorwegianConnectionsgeometrical opticsEntityWKB approximationEntityCategoriesGeometrical opticsNonlinear partial differential equations