Chebfun Clifford algebras Darboux transforms Darboux-Bäcklund transformation Euler equation Euler equations KdV type hierarchies Korteweg–de Vries–Burgers equation Lagrangian curve flows Levi–Civita connections Mathematics & science Navier–Stokes equations Research & information: general Spin groups Sturm–Liouville adjoint-symmetry chebop clamped contact spaces contact symmetry cylindrical and spherical waves differential coverings differential invariants discretization drift eigenpairs error control exact solutions free resolution geometrical formulation