Spectral asymptotics of systems of differential operators that are Douglis-Nirenberg elliptic in domains of finite measure (Q1594189)

This paper studies the spectral asymptotics for some non selfadjoint elliptic systems of Douglis-Nirenberg type having arbitrary diagonal type on domains with finite measure. It is assumed that the distribution function of the eigenvalues of the operators involved follows a classical asymptotic formula. The main theorem states that the spectrum is discrete and provides an asymptotic estimate for the number of eigenvalues located in some sectorial regions.