By considering negative surgeries on a knot in , we derive a lower bound on the nonorientable slice genus in terms of the signature and the concordance invariants ; this bound strengthens a previous bound given by Batson and coincides with Ozsváth–Stipsicz–Szabó’s bound in terms of their invariant for L-space knots and quasi-alternating knots. A curious feature of our bound is superadditivity, implying, for instance, that the bound on the stable nonorientable slice genus is sometimes better than that on .
"Correction Terms and the Nonorientable Slice Genus." Michigan Math. J. 67 (1) 59 - 82, March 2018. https://doi.org/10.1307/mmj/1511924604