Sign up ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

Crossposted to mathoverflow

Let $W$ be the finite $\mathbb{Z}$-module obtained from $\mathbb{Z}_q^n$ with addition componentwise. Let $V$ be a submodule of $W$. Let $V^{\perp} = \{w \in W \, : \, \forall v \in V \quad v.w = 0 \}$ where "." is the dot product. Is it true that ${(V^{\perp})}^{\perp} = V$?

share|cite|improve this question
I would use the notation $V^{\perp}$. –  Qiaochu Yuan Sep 12 '11 at 22:26
I don't think you waited long enough before crossposting. I would give it at least a day. –  Qiaochu Yuan Sep 13 '11 at 2:04

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.