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I have the following statement:

$$1< d,q < a .$$

Does this mean:

$1 < d$ and $q < a$?

or does it mean:

$1< d < a$ and $1< q<a$?

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The second one. – J. M. Oct 21 '11 at 16:00
up vote 1 down vote accepted

J.M. is correct, assuming that the author of the statement $$1 < d,q < a$$ formatted their statement the way they should have. One could imagine intending to say $$\ldots 1<d,\text{ and }q<a\ldots $$ but forgetting the general rule to insert words between distinct expressions (to avoid precisely this kind of confusion). So, assuming they meant the single expression $1 < d,q < a$, then it does mean the second one, i.e. " $1<d<a$ and $1<q<a$ ". However, if they were sloppy and wrote two expressions right next to each other separated only by a comma, i.e. $1<d$, $q<a$, then they intended the first one, i.e. " $1<d$, and also $q<a$ ".

But it's best to assume people mean what they say unless there's reason to believe otherwise (e.g., the statement that $1<d$ and $q<a$ doesn't make sense in the context in which this appears). So you should read it as the second version.

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