General Grammar

Common mistakes

  1. If you’re one of my students, then please spellcheck, and please proofread before having me read your work. It’s good to see what mistakes you can catch by yourself. I’ll pretty much always correct something, yes, but it takes a long time to carefully read these papers already, and it’s harder when obvious mistakes are present.  (And I’ll also admit that I will change something, then change it back a few revisions later to the way you had it. So you really shouldn’t necessarily take all my edits as “fixing a mistake.”) Spellcheck won’t fix everything. If you write loose instead of lose, or then instead of than, etc., it’s only going to be fixed by our attention to detail.
  2. Is it nonincreasing or non-increasing? Is it nonlinear or non-linear? Is it subroutine or sub-routine? Guideline: if we use the word frequently, then don’t use a hyphen. (So the answer would be “the former” in all of these cases.) The main rule: Just be consistent. Don’t write non-linear one place, and nonlinear another. I’m not good about this, so I always have to search for “non” before submitting a paper, and make sure it’s been written consistent throughout.
  3. Corollary: what about reiterate versus re-iterate? I think the former is almost universal. But be careful that you don’t form a new word. In the case of “resolve” versus “re-solve,” when you mean “to solve again,” I always prefer the latter. The former is a different word with a different meaning, which could (unlikely but possibly) confuse with “to solve again.”
  4. Do periods come inside or outside parentheses?  Depends on if it’s an entire sentence starting inside parentheses. Consider this sentence (in which the parenthetical thought does not contain an entire sentence, and in which the sentence itself starts outside the () brackets).  (But here, the period goes inside.)
  5. “Which” versus “that”:  Long story.  I’m going to refer you to Grammar Girl on this (it’s overkill for me to ask you to listen to GG’s podcast or column, but it’s a nice resource).

    One note:  this rule is not absolutely set in stone.  It’s sometimes very awkward to get it right, and the sentence can read better if you misuse the rule.  If the sentence is truly awkward and would read so much better if I let you use “which” instead of “that,” well, then go ahead and do it.  But for the most part, just pay attention to whether the clause started by which/that is restrictive or not.  If it is (you have to have the clause or else the preceding sentence doesn’t make sense), then use “that” without a comma before it.  If not, use “, which …” as stated in the guide.
  6. Subsections. Many people love to use subsections, subsubsections, etc. Use this when it helps organize the paper and makes the reader’s life easier, but don’t overuse them. No “orphan subsections” are allowed: That is, if you have a Section 2.1, there needs to be a Section 2.2.
  7. What are the rules on capitalization for Table or table? Figure or figure? Journals each have their own rules on this, but by far the most common rule is to capitalize Figure if you’re talking about a specific figure.  “See Figure 3 for an explanation.”  If you don’t refer to the figure number, leave it lower-cased.  “As we demonstrated in this figure, our algorithm is useless.”  Same with table, section, theorem, etc.
  8. i.e. = “that is”
    e.g. = “for example”
    et al. = “and others”

    Note 1:  Don’t start a sentence with i.e. or e.g. (or et al. for that matter, not that you’d be tempted to!); hence, these are always lower case.  (I’m not sure this is an absolute rule throughout the universe, but it is for our papers.)

    Note 2:  Always put a comma after i.e. and e.g. “(i.e., problem P is bounded)” or “(e.g., such as demonstrated by Geunes et al.)”

    Note 3:  et doesn’t get a period; it’s not an abbreviation because et is the whole Latin word…however, al. is an abbreviation. So it’s got to be et al. and not et. al. or et al or other combinations.

    Note 4:  As discussed below, watch out that al. doesn’t inadvertently end a sentence, and use that one-space character in LaTeX (e.g., “Geunes et al.\ show that if P = NP, we are out of a job”).
  9. Oxford comma:  Is it “a, b, and c” or “a, b and c”? The official rules are that either one is correct, but the latter is only correct when confusion does not occur due to the omission of the last comma. My thoughts: Why make a judgment call on when the last comma is necessary? If you’re a student writing a paper with me, let’s just always use the comma before “and” in a list of three or more items.  (That last comma is sometimes called an “Oxford comma.”)
  10. Speaking of separating items in a list, I’ve seen semicolons sometimes when the items in a list are complex thoughts.  (For instance, “Some advantages of our algorithm are that it executes correctly over thirty percent of the time without causing a segmentation fault; the code is very brief and easy to debug; and we make absolutely no claims as to its validity.”)  I only rarely do this, but if the thoughts really are very long, it makes sense to do this. Alternatively, sometimes it might be better just to rewrite the sentence, because a sentence containing a series of complex items is going to be rather long.
  11. Not worth worrying about, but there’s also the issue of periods and commas in quotes. I put periods (.) and commas (,) inside quotes always (ok, one exception) because I’m American. Long story, and we use so few quotes in our papers that it’s not worth paying much attention to. But for instance, before this, I wrote “fixing a mistake.” That’s correct in US grammar. Not in the UK: You’d write “fixing a mistake”.  Or, “fixing a mistake”, if it were followed by a comma (with the comma going inside the quotes in US grammar).  The one exception we agree on:  If the quote is around a symbol.  For instance:

    We denote this situation with the label “O”.

    (Would you believe that this did come up in a paper?)