Learn English – Do you write sometimes equation with capital letter

numbers

I know that usually 'proposition, theorem, lemma' are written only with capital letter if they refer to a number. Example:

As seen in last theorem, this is all trivial.

and

As seen in Theorem 1, this is all trivial.

Now I wonder, is this also the case for equation and property? Which one of the following would be correct?

As seen in equation (2.3), property (1.4) is fulfilled for the operator.

or  

As seen in Equation (2.3), Property (1.4) is fulfilled for the operator.

Best Answer

Generally speaking, I'd say if you use it for one reference type, you should use it consistently for others as well. The best way of justifying it would be that when you give a specific number to an object, "Equation (number)" becomes the title of that object, whereas something like "the aforementioned equation" is a more general term.

In my field "Theorem", "Property" and "Lemma" aren't usually things that are referred to as such in writing (pretty sure this just depends on which subject area you're writing for), but certainly if e.g. "Section 3" and "Figure 5(a)" are capitalised, so too should "Equation 2.3".

I also see many cases where such references are abbreviated to "Fig.", "Sec.", "Eq.", etc if they are in the middle of a sentence and left as "Figure", "Section", "Equation" if at the start of one - but as far as I can tell, this is just a matter of personal taste unless a specific style has been demanded by a journal. Just make sure that whichever one you use, you remain consistent throughout the text.

(as an aside: In your first example, As seen in last theorem would become As seen in the last theorem if anything; but As seen in Theorem 1 would generally be preferable to avoid any ambiguities)

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