Non-analytical reals strongly relativizing \(\Delta^0_1\) at Baire space

Determine whether there exist non-\(\Delta^1_1\) reals that strongly relativize \(\Delta^0_1\) at Baire space \(N\), and whether continuum many such reals exist.

Background

The paper proves that every Π10\Pi^0_1-singleton in Baire space strongly relativizes Δ10\Delta^0_1 at NN. It also notes that every Δ11\Delta^1_1 real is computed by a Π10\Pi^0_1-singleton, while not every Δ11\Delta^1_1 real is itself a Π10\Pi^0_1-singleton. This motivates asking whether the class of strongly relativizing reals at NN extends beyond the Δ11\Delta^1_1 reals and how large that extension might be.

References

This leaves us with the following question. Are there non-$\Delta1_1$ reals which strongly relativize $\Delta0_1$ at $N$? Are there continuum-many?

Strongly relativizing reals  (2608.14488 - Arant, 14 Aug 2026) in Section 3, remark (3) following Theorem \ref{thm:pi01singleton}