Question

(Partial Diff Eq nomenclature question): I've seen both the Grad symbol and an upright facing triangle used to represent the discriminant of a 2nd order PDE (canonical forms/hyperbolic/elliptic/parabolic thing); are both common notations in your guys experience, or is one more common than the other, or what?

Answer 1

@ganeshie8 @Kainui @iambatman @Directrix @anybodywhohasdonePDEplshalp

Answer 2

I've never used a symbol to represent a discriminant, I prefer to use the triangles for things like gradient and the Laplacian.