I encounter the following problem in Evan's PDE:
I feel I should use the property: 
but don't know how to proceed.
Asked
Active
Viewed 162 times
1
-
@Harry49 is right, and you can use the method in that link. Another easier proof is roughly speaking to use the test function $v(x,t)=1_{{ t< t_0}}$ in the weak formulation (i) and the property falls right out. Of course you need to approximate $v$ by smooth functions to make it rigorous. – Jeff Jan 08 '18 at 18:25