On a regularization of index 3 differential-algebraic equations

In Hanke [J. Math. Anal. Appl. 151 (1990) 236-253], boundary value problems for linear differential-algebraic equations (DAEs) with time-varying coefficients A(t)x′(t) + B(t)x(t) = q(t) tractable with index 2 are considered. In this paper, we consider index 3 DAEs in an analogous way. A transferable DAEs is obtained by the regularization and the convergence rate is derived.