1

For the determiner in English, I learn that they are used in many different situations. For example, a is used before a noun. However, sometimes I misuse it. Therefore, I would like to understand it, so I can write my sentence correctly.

For example,

I have a vector of random variables.

As I understand, a in this sentence is a determiner used to identify the vector, not the random variables. Hence, it is correct to say:

Let X be a vector of random variables.

Because in this sentence, the determiner a refers to the vector X and did not refer to the random variables. Is that correct? if not, then, why?

However, similar to this sentence, I would like to specify the dimension of this vector. So, is it ok to say:

Let X be an n-dimensional vector of random variables.

Or I must not use the determiner an here because n-dimensional is plural in its meaning. Is that correct?

So, which sentence is correct?

5
  • 3
    About the word, "purple" in your question: is it possible you mean, "plural" [meaning "two or more"]? ... And not just in this question, but also other questions you have recently asked? ... ["Purple" being a color-name] – Lorel C. Jan 13 '19 at 6:18
  • Unable to edit it though, sorry. – Lorel C. Jan 13 '19 at 6:28
  • 1
    n-dimensional is an adjective, not a noun. It cannot be plural/singular any more than, say, long or red – Jyrki Lahtonen Jan 13 '19 at 7:13
  • +1 @JyrkiLahtonen Thank you so much. I really learn a new thing. – Maryam Jan 13 '19 at 7:32
  • 1
    The main function of a determiner is to mark an NP as definite or indefinite. – BillJ Jan 13 '19 at 8:25
2

Yes, that's correct.

The essential noun in the sentence is vector, which requires an indefinite article:

I have a vector.

This doesn't change if you qualify it with an additional noun phrase, no matter if that additional portion of the noun phrase is singular or plural:

I have a vector (of X and Y).

Nor does it change if you use an adjective in front of it, regardless of the singularity or plurality of the adjective:

I have a (Z) vector (of X and Y).

The consideration of the article is based only on the noun itself, not how it's being modified by other things.


I say that, but in the one example you gave, the form of the indefinite article changes from a to an because of the vowel sound of n-dimensional that comes immediately after it:

Let X be an n-dimensional vector of random variables.

But if the adjective started with a consonant sound, you would use a again:

Let X be a four-dimensional vector of random variables.

Both a and an are used for a singular noun: vector in this case.


If vector itself became plural, then the indefinite article would be dropped because you would no longer have a single vector:

I have vectors.
I have vectors of random variables.
I have vectors that are long.
I have single-dimensional vectors of random variables.
I have n-dimensional vectors of random variables.

The consideration of using the indefinite article or not is based only on the use of vector or vectors.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.