Error Detection Capability of Linear Code

Theorem
Let $C$ be a linear code.

Let $C$ have a minimum distance $d$.

Then $C$ detects $d - 1$ or fewer transmission errors.

Proof
Let $C$ be a linear code whose master code is $V$.

Let $c \in C$ be a transmitted codeword.

Let $v$ be the received word from $c$.

By definition, $v$ is an element of $V$.

Let $v$ have a distance $f$ from $c$, where $f \le d - 1$.

Thus there have been $f$ transmission errors.

As $d$ is the minimum distance it is clear that $v$ cannot be a codeword of $C$.

Hence it can be understood that $C$ has detected that $v$ has as many as $d - 1$ transmission errors.