Semigroups and Weakly Elliptic Operators
Quan Zheng · Acta Analysis Functionalis Applicata · 1999
Let iAj (1≤j≤n) be commuting generators of bounded C_0-groups, P(A)=sum form ｜μ｜≤2aμA~μ(A~μ＝ A_1~μ1…A_n~μn). If P is weakly elliptic and the real part of P is bounded above, we show that P(A) generates a C_0-semigroup.