I want to use Reduce to my own function, but it generates the error message: This system cannot be solved with the methods available to Reduce. Here is a simplified example.
test[x_] := x^2 - 3 /; 0<x<10; test[x_] := -1 /; 10<x Reduce[test[x]<1, 0<x<5]
/; makes the problem. However, how can I define the domain of my own function without using