Improved Johnson-type Bounds for Insertion-Deletion Codes

We improve upon the Johnson-type bound of Hayashi and Yasunaga for insertion-deletion codes by encoding each local list into a binary constant-weight code. The resulting local list-size bound is tight for sufficiently large alphabets. Applying the McEliece--Rodemich--Rumsey--Welch bound to this constant-weight formulation yields an asymptotic rate bound that strictly improves on Yasunaga's Elias-type bound in the nontrivial range.