An additive complement of a set of nonnegative integers
is a set
of nonnegative integers
such that the sumset
contains all sufficiently large integers.
For infinite additive complements, write
and
for the numbers of their elements at most
.
Zhang (2026) gave a discrete proof of the sharp implication
The threshold is strict. At equality, examples have for infinitely many
.
Zhang (2026) reports ChatGPT assistance in exploring relations between gaps and Codex assistance in checking and revising proof details.