Using the following definition:
Reduction: There is a polynomial-time reduction from problem $X$ to problem $Y$ if arbitrary instances of problem $X$ can be solved using:
- Polynomial number of standard computational steps, plus
- Polynomial number of calls to oracle that solves problem $Y$.
Notation $X \leq_{P} Y$
Say we had the case where $X$ can be solved in polynomial time using $O(n\log n)$ of computational steps, with zero calls to the oracle / black box used to solve instances of $Y$.
Can we still say $X \leq_{P} Y$? As 0 still classifies as a polynomial number of calls to the oracle that solves problem $Y$, and a polynomial number of standard computation steps were used to solve $X$.