YES

Problem:
 app(nil(),xs) -> nil()
 app(cons(x,xs),ys) -> cons(x,app(xs,ys))

Proof:
 Matrix Interpretation Processor: dim=1
  
  interpretation:
   [cons](x0, x1) = x0 + x1 + 6,
   
   [app](x0, x1) = x0 + x1 + 4,
   
   [nil] = 0
  orientation:
   app(nil(),xs) = xs + 4 >= 0 = nil()
   
   app(cons(x,xs),ys) = x + xs + ys + 10 >= x + xs + ys + 10 = cons(x,app(xs,ys))
  problem:
   app(cons(x,xs),ys) -> cons(x,app(xs,ys))
  Matrix Interpretation Processor: dim=1
   
   interpretation:
    [cons](x0, x1) = 5x0 + x1 + 1,
    
    [app](x0, x1) = 5x0 + x1 + 1
   orientation:
    app(cons(x,xs),ys) = 25x + 5xs + ys + 6 >= 5x + 5xs + ys + 2 = cons(x,app(xs,ys))
   problem:
    
   Qed