FPTAS and NP-Completeness

[heliodromus]

Hey fellas,

 

I have a Problem in understanding on how to proof the following:

 

Let Q = {max,f,L} be a NPO-Problem, where f only supports integers.

 

L_Q^* ={(x₀,1^k)|there exists x such that L(x₀,x) and f(x₀,x) >=k}

The instance of x₀ is binary coded while the numerical parameter k is unary coded.

 

Show that if L_Q^* is NP-Complete, then there is no full polynomial approximation scheme for Q.

 

Normally I have so sort of idea, but this time I am really stumped

 

I would be grateful if you could show me on how to solve such issues.

 

Sincerely yours

heliodromus