I tend to use Option 1, with the restatement listed as

\begin{lemma}[Restatement of Lemma 3.1] xxxx \end{lemma}

Alternatively, "For the convenience of the reader, we restate Lemma 3.1."

But I'm not sure how good a question this is for MO, since it certainly doesn't have a specific answer, you'll undoubtedly receive different opinions. Finally, specific journals may have their own preferred styles for doing this, in which case that's the one to use.

I tend to use Option 1, with the restatement listed as

\begin{lemma}[Restatement of Lemma 3.1]
xxxx
\end{lemma}

Alternatively, "For the convenience of the reader, we restate Lemma 3.1."

But I'm not sure how good a question this is for MO, since it certainly doesn't have a specific answer; you'll undoubtedly receive different opinions. Also, specific journals may have their own preferred styles for doing this, in which case that's the one to use.

I tend to use Option 1, with the restatement listed as

\begin{lemma}[Restatement of Lemma 3.1} xxxx \end{lemma}

Alternatively, "For the convenience of the reader, we restate Lemma 3.1."

But I'm not sure how good a question this is for MO, since it certainly doesn't have a specific answer, you'll undoubtedly receive different opinions. Finally, specific journals may have their own preferred styles for doing this, in which case that's the one to use.

I tend to use Option 1, with the restatement listed as

\begin{lemma}[Restatement of Lemma 3.1] xxxx \end{lemma}

Alternatively, "For the convenience of the reader, we restate Lemma 3.1."

But I'm not sure how good a question this is for MO, since it certainly doesn't have a specific answer, you'll undoubtedly receive different opinions. Finally, specific journals may have their own preferred styles for doing this, in which case that's the one to use.