I am trying to use NDSolve on a system of partial differential equations that has a delay. The difficulty seems to be in the syntax for the initial condition: I have tried, for example, h[x,t/;t?0]==1, but I get 2 error messages:

"The arguments should be ordered consistently."

"To avoid possible ambiguity, the arguments of the dependent variable in h[x,t/;t<=0]==1 should literally match the independent variables."

If I put a trivial condition on the x, such as h[x /; x < Infinity, t /; t <= 0] == 1, then the 1st error message disappears, but the 2nd remains.

Is there a syntax that will work?