Second-order equations and local isometric immersions of pseudo-spherical surfaces

Nabil Kahouadji (1) , Niky Kamran (2) , Keti Tenenblat (3)

1 Department of Mathematics, Northwestern University
2 Department of Mathematics and Statistics [Montréal]
3 Department of Mathematics, Universidade de Brasìlia

We consider a class of differential equations that describe pseudo-spherical surfaces of the form $u_t=F(u,u_x,u_{xx})$ and $u_{xt}=F(u, u_x)$. We answer the following question: Given a pseudo-spherical surface determined by a solution $u$ of such an equation, do the coefficients of the second fundamental form of the local isometric immersion in $\mathbb{R}^3$ depend on a jet of finite order of $u$? We show that, except for the sine-Gordon equation, where the coefficients depend on a jet of order zero, for all other differential equations, whenever such an immersion exists, the coefficients are universal functions of $x$ and $t$, independent of $u$.

Mots clés: Evolution equations; nonlinear hyperbolic equations; isometric immersions; pseudo-spherical surfaces; isometric immersions.

Domaines: Géométrie différentielle [math.DG]

Nabil Kahouadji, Niky Kamran, Keti Tenenblat. Second-order equations and local isometric immersions of pseudo-spherical surfaces. 2013. ⟨hal-00855710v1⟩