# Ending sentences in an aligned equation [duplicate]

This is more of a general "mathematical english/punctuation" question, but I figure TeX users will know the answer. The following sentence seems natural:

We define the $xyz$ constant via $xyz=\int_0^\infty f(y)dy$.


Note the period at the end, which is of course correct. What if I decide to align the equation for $xyz$?

We define the $xyz$ constant via

\begin{align}
xyz=\int_0^\infty f(y)dy
\end{align}


Should I still place a period at the end of this sentence (in the aligned equation)? Is it considered bad form to end sentences in the middle of aligned equations like this?

Thanks!

• I certainly would recommend putting a period there. I know many textbooks do not do that for displayed equations, but I feel that math should really have a sentence structure and hence my preference for the period. – Peter Grill Apr 10 '14 at 4:12
• – Werner Apr 10 '14 at 4:13
• @Werner or indeed here: tex.stackexchange.com/questions/7542/…, which I just now found. – icurays1 Apr 10 '14 at 4:15