Topological structure of elliptic boundary problems in space (Q761640)

Let G be a domain in \(R^ n\) bounded by a smooth surface \(\Gamma\). An elliptic \(m\times m\) system of integro-differential equations is considered in G. General boundary data satisfying the complementing condition are prescribed. The symbolic matrix of the operator in G generates some matrices \(F_+(x,\lambda ')\) and \(\Omega_+(x,\lambda ')\) where \((x,\lambda ')\in \Gamma \times S^{n-2}.\) The author states that the degrees of \(F_+\) and \(\Omega_+\) are topological invariants which define the connectivity components of Fredholm first and, respectively, general boundary value problems.