Prolongation Projection Commutativity Theorem
Prolongation Projection Commutativity Theorem
<!-- *** Custom HTML *** --> If the symbol $g_k$ of a SPDE $R_k$ is 2-acyclic, then the operations of prolongation and projection on $R_k$ commute \[ \rho^{k+l+2}_{k+l+1}((R_k)_{+l+2}) = \left(\rho^{k+l+1}_{k+l}((R_k)_{+l+1})\right)_{+1}.\] We apply this to study contact of three-dimensional CR-manifolds.