This paper deals with the extinction of weak solutions of the initial and boundary value problem for ut=div((|u|σ+d0)|▽u|p(x)-2▽u).When the exponent belongs
<正> For an integer n≥2,we say that an operator A is an n-idempotent ifA~n=A;A is a generalized n-idempotent if A~n=A~*;A is a hyper-generalized n-iclempotent