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Alternatives to “and/or”?

Is it okay to say "and/or"? How else might I phrase a sentence like the following?

The amount of happiness displayed by the bunny increased when either the bunny was well fed and/or when the bunny was watching a sunset.

I am writing a scientific paper, and it is important that the events have the same effect when they occur separately or together; I have written a trivial example replacing esoteric words with more familiar ones.

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marked as duplicate by Kosmonaut Feb 17 '11 at 1:44

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

Shouldn't the title say "...and/or how else might I achieve this?" ;-)

In the sentence as presented, the use of the initial "either" really requires that you follow it up only with an "or"; "either/and" just doesn't work. If the options given are not inherently exclusive, they should be understood to be "one, the other, or both".

Alternatively, you could say "the amount of X increased when Y, and also when Z."

Or, "the amount of X increased when Y, or when Z (increasing linearly/exponentially/whatever when both Y and Z)."

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thanks for the tip. I must have been over thinking this; I changed the title according to your excellent suggestion. – David LeBauer Feb 14 '11 at 23:35

If it's used repeatedly in your paper and it's important to specify, then I'd probably stick to "and/or" if the intention is clear: it's fairly widely used and, compared to adding a parenthesis such as "(or where both cases hold)", it has the merit of being concise.

I also wouldn't get too bogged down: if the editor really doesn't like it for some reason, they'll change it or ask you to change it. For what it's worth, I translate professionally (both academic material and more general texts) and have never been asked to avoid "and/or".

[Conversely, for my own sanity, I have stopped using "iff" for "if and only if" after this 'misspelling' was highlighted to me various times.]

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But what's wrong with iff? :) – Marthaª Feb 15 '11 at 1:29

I believe a scientific paper is expected to use fairly literate English, so use of short-cuts such as "and/or" might be inappropriate.

However your peer reviewers are likely to be preoccupied with the appropriateness of "bunnies" enjoying sunsets, so it won't detract greatly from the result.

If "it is important [to record] that the events have the same effect when they occur separately or together" - why not just say so?

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As you have used either in the first part of your sentence, the second part of the sentence must only use or, as either-or is a complementary pair, one must follow the other. Either-and would not make the correct grammatical sense.
In the above case, the use use of either-or and and would make two drastically different sentences.

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I've heard the term "XOR" used in casual conversation, but only among math/computer nerds like myself. If more people accepted the term it would make things a lot easier.

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"A xor B" does not mean "A and/or B". It means "A or B, but not both" (i.e., "exactly one of A and B"). If you're going to use a technical word and use it incorrectly, you'll just confuse nearly everyone. – ShreevatsaR Feb 15 '11 at 6:08
@ShreevatsaR However, if "xor" was used then "or" could be used in its boolean sense meaning "and/or" without any ambiguity. But I can't really see that taking off in non-geek English. – neil Feb 15 '11 at 12:38
@neil that might be acceptable on a technical paper if the terms are defined that way – jk. Feb 15 '11 at 18:16
@neil. Thanks, that's what I meant. I just realized how unclear my answer was. – Yitzchak Feb 21 '11 at 18:02

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