= Correctable Pauli error radius
{title2=$t=\lfloor(d-1)/2\rfloor$}
The guaranteed radius is the largest integer $t$ for which all unknown-location <Pauli operators> of weight at most $t$ can be corrected together. Pairwise products have weight at most $2t$, so $2t<d$ suffices by the <Knill--Laflamme condition>. Conversely, split a minimum-weight undetectable Pauli operator between two subsets of its support. If $d\leq2t$, this gives two errors of weight at most $t$ whose pairwise product violates that condition. Consequently $d$ is either $2t+1$ or $2t+2$; parity cannot be recovered from $t$ alone.
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