ASYMPTOTICS OF THE DENSITY OF STATES OF HYPOELLIPTIC ALMOST PERIODIC OPERATORS
V I Bezjaev · Mathematics of the USSR-Sbornik · 1978
For a hypoelliptic differential operator with almost periodic coefficients asymptotics are found for the density of states, complete with a remainder term. Under certain conditions on the symbol of the operator the asymptotics imply an estimate on the length of the gaps in the given operator acting in L2(Rn). Bibliography: 25 titles.