This man is the first namesake of a linear partial differential equation that is elliptic or hyperbolic for negative or positive values of the Tchaplyguine variable.  
This man is the first namesake of a linear partial differential equation that is elliptic or hyperbolic for negative or positive values of the Tchaplyguine variable.  In addition to that equation for transonic flow partially named for Tricomi, this man lends his name to a criterion that can be used to calculate Legendre symbols.  One of this man's theorems states that the operator x dot grad returns n times f of x when applied to a smooth function f of x that is homogeneous of degree n.  This man's namesake fluid description uses a frame that is fixed in space, as opposed to the Lagrangian description.  Carmichael's theorem generalizes a theorem due to this man that involves this man's namesake totient function.  FTP name this solver of the bridges of Königsberg problem whose namesake number is the base of the natural logarithm.
This man is the first namesake of a linear partial differential equation that is elliptic or hyperbolic for negative or positive values of the Tchaplyguine variable.  
Leonhard {Euler}