I have seen a few tips regarding the placement of periods before or after the closing parenthesis, but none of them solves my issue. A general rule of thumb-if the words inside the parentheses form a complete sentence, then period before closing it, otherwise period after closing it. However I am writing a sentence in the introduction part of a paper and the following options seem to be there

  • <,> denote the generalised inner product (see Section IV).
  • <,> denote the generalised inner product (see Section IV.)
  • <,> denote the generalised inner product (see Section IV.).

Which one among them is correct? A double period seems superfluous while placing it either inside or outside seem not to do justice to the whole sentence. Are there different conventions for British, American or Australian systems?


Only place the period inside parentheses if it forms a complete sentence that stands on its own. (For example, this is a complete, independent sentence.) Otherwise, place the period outside the parentheses (treat this like a subordinate clause, with no initial capital or period of its own).

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    Lovely and succinct. – Edwin Ashworth Aug 31 '13 at 8:18
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    This gets more complicated with sentences like this one (did you notice the parenthetical question?). If the phrase in the parentheses needs a different punctuation mark than the one that closes the parent sentence. Also, the placing of punctuation within or outside parentheses is one of the differences between BrEn and AmEn and the rules are not as clear as all that. – terdon Aug 31 '13 at 13:35
  • Classifying these pseudorules as BrEn or AmEn gives the impression that (1) almost all natives of the UK and the USA adhere to the 'law of the land' in this area (2) it is important to do so. Neither is true. – Edwin Ashworth Aug 31 '13 at 16:41
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    @terdon Good point about the question mark. In more complex cases, it might make sense to follow rules closer to the ones for quotations. – Bradd Szonye Sep 1 '13 at 1:37

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