The code covering radius of an error-correcting code
is the greatest Hamming distance of a word
to its nearest codeword:
Here
is the alphabet and
is the Hamming distance.
A word attaining this greatest distance is a deep
hole. Thus Hamming distance balls of radius
about the codewords cover
.
For the first-order Reed-Muller code on nine variables, Wang et al. (2026) proved that .
For the third-order Reed-Muller code on eight variables, Zhao and Wu (2026) proved that .