# Thread: the set - singular or plural

1. ## the set - singular or plural

From a physics book:
"The set of unitary 3x3 matrices with det U = 1 form the group SU(3)."

I think it should read forms - singular. What do you think?

Take a look at the following similar examples:
The set of real numbers is a field.
The set of all 3x3 square matrices does not form a group.
The set of all beautifull English words forms a nice book.

In all of them "The set of (some plural)" seems to play the role of a single singular unit. Am I wrong about it?

PS Feel free to correct any mistakes in this post

2. ## Re: the set - singular or plural

Originally Posted by ymnisky
From a physics book:
"The set of unitary 3x3 matrices with det U = 1 form the group SU(3)."

I think it should read forms - singular. What do you think?

Take a look at the following similar examples:
The set of real numbers is a field.
The set of all 3x3 square matrices does not form a group.
The set of all beautifull English words forms a nice book.

In all of them "The set of (some plural)" seems to play the role of a single singular unit. Am I wrong about it?

PS Feel free to correct any mistakes in this post
Take a look at the following similar examples:

The set of real numbers is a field. - This is correct because the subject is "set" - one set singular; therefore, use the "s" form of the verb.

The set of all 3x3 square matrices does not form a group. - The same thing goes for this sentence as the one above.

The set of all beautifull English words forms a nice book. - The same thing goes for this sentence as the first two. The subject is "set" - one set.

One may easily feel inclined to use a plural verb in such sentences, and indeed some native speakers of English do. This is because the verb immediately follows a plural noun. However, the plural noun in all three sentences here is part of a prepositional phrase that follows a singular subject.

In all of them "The set of (some plural)" seems to play the role of a single singular unit. Am I wrong about it? <<

You are correct, and this is why we use the "s" form of the verb for present simple, which indicates a singular subject, not plural.

"The set of unitary 3x3 matrices with det U = 1 form the group SU(3)."

I think it should read forms - singular. What do you think? <<

It's hard to tell here. They use an equal sign. It depends on how many forms the set makes.

3. ## Re: the set - singular or plural

Originally Posted by PROESL
Take a look at the following similar examples:

The set of real numbers is a field. - This is correct because the subject is "set" - one set singular; therefore, use the "s" form of the verb.

The set of all 3x3 square matrices does not form a group. - The same thing goes for this sentence as the one above.

The set of all beautifull English words forms a nice book. - The same thing goes for this sentence as the first two. The subject is "set" - one set.

One may easily feel inclined to use a plural verb in such sentences, and indeed some native speakers of English do. This is because the verb immediately follows a plural noun. However, the plural noun in all three sentences here is part of a prepositional phrase that follows a singular subject.

In all of them "The set of (some plural)" seems to play the role of a single singular unit. Am I wrong about it? <<

You are correct, and this is why we use the "s" form of the verb for present simple, which indicates a singular subject, not plural.

"The set of unitary 3x3 matrices with det U = 1 form the group SU(3)."

I think it should read forms - singular. What do you think? <<

It's hard to tell here. They use an equal sign. It depends on how many forms the set makes.
I agree with PROESL. The emphasis is on a set (which is singular).

4. ## Re: the set - singular or plural

Originally Posted by PROESL

"The set of unitary 3x3 matrices with det U = 1 form the group SU(3)."

I think it should read forms - singular. What do you think? <<

It's hard to tell here. They use an equal sign.
I am sure that sentence has been revised many times before publication. And I would like to be sure about it. Since you agreed with all the previous examples I made up, I am almost convinced that the original sentence is wrong.

That sentence means:
"The set of unitary 3x3 matrices with unity determinant form(s) the group SU(3)."
or "The set of unitary 3x3 matrices which have determinant equal to one form(s) the group SU(3)"
By the way SU(3) is the name of the group (a special mathematical structure).

It is the same idea as:
The set of all beautiful English words with a th sound forms a nice book.
or
The set of all beautiful equations with the solution x = 1 form the group Noname(Yet).

Originally Posted by PROESL
It depends on how many forms the set makes.
In the original sentence the set does not make any form.
The set contains all the matrices 3x3 which have a special property,
that is, all the 3x3 matrices which have determinant equal to one.
This special set forms the group SU(3). This special set is the group SU(3).

I think in the original sentence the verb form could mean also comprise.

5. ## Re: the set - singular or plural

Originally Posted by ymnisky
I am sure that sentence has been revised many times before publication. And I would like to be sure about it. Since you agreed with all the previous examples I made up, I am almost convinced that the original sentence is wrong.

That sentence means:
"The set of unitary 3x3 matrices with unity determinant form(s) the group SU(3)."
or "The set of unitary 3x3 matrices which have determinant equal to one form(s) the group SU(3)"
By the way SU(3) is the name of the group (a special mathematical structure).

It is the same idea as:
The set of all beautiful English words with a th sound forms a nice book.
or
The set of all beautiful equations with the solution x = 1 form the group Noname(Yet).

In the original sentence the set does not make any form.
The set contains all the matrices 3x3 which have a special property,
that is, all the 3x3 matrices which have determinant equal to one.
This special set forms the group SU(3). This special set is the group SU(3).

I think in the original sentence the verb form could mean also comprise.

Okay, I think I understand what you're getting at now. It should always be "set forms". It should really be a singular verb - simple present, third person singular "s" form.

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