The Weird English Language
Hi Friends 
Whilst preparing for my next exams (and waiting for ACII to be released on PC) I stumbled over this one:
> Who, besides mathematicians, care about Boolean rings?
Are multiple people meant with «who»? And if yes, why? Because of the mathematicians (plural too), or is it that way in general?
Granjow
Yes, multiple people are meant by "who." Notice the word "care" is not "cares." The verb would be "cares" if the subject is singular; whereas, if the subject is plural, it would be "care." So because "care" is used when a subject is plural, we can conclude that "who" is also plural in this case. The other subject, mathematicians, does not influence the verb "care," because it is an unrelated subject. It could easily be cut out of the sentence, so nothing changes.
Actually I think you're wrong, FLAE. Who is always singular, and the sentence should say "who... cares", not "who... care".
for example,
Who(singular) cares(singular)?
He(singular) cares(singular)
Who are the people (plural) who care(plural)?
They(plural) care(plural)
I don't know if that answers the OP's question, tho. The original question is ambiguous; it could be a single person or multiple people.
The same as this question:
Who, besides besides my mom, loves me?
Could be one person, could be more. The form of the words in the sentence, either singular or plural, don't change that fact, even tho the sentence is grammatically correct.
Who can definitely be singular or plural, just as the word 'you' can singular or plural. FLAE is correct.
Let's drop "besides mathematicians" from the original sentence:
*Who care about Boolean rings?
I've used the asterisk (*) notation from linguistics to mark this sentence as ungrammatical, where the working definition of ungrammatical is "sounds wrong to native speakers". It definitely sounds wrong to me. Are there any native speakers of English here who think it sounds correct?
Let's look at the conjugations of the verb "to care":
I care
you care
he/she/it cares
we care
you (plural, y'all) care
they care
As you can see, "cares" does not indicate plurality. It's only used for third person singular. There's no reason to expect "care" to change to "cares" when the subject is plural. In fact, "he cares" when pluralized changes to "they care".
"Who" can refer to one or many people. In my dialect, at least, if the subject is "who" then the verb which follows is always conjugated as third person singular: "Who cares?"
As a disclaimer, I would like to mention that all of my information is based on college-level Canadian Technical English courses. Some rules are different from the United States and from England, as well as other regions. As far as I am aware, the following information is not subject to region, but that is merely an assumption. I apologize in advance if this rule is not universal. 
Technically, "who care about ... " is correct when talking specifically about plural individuals. But most English speakers do not use it properly. True, you are speaking to which sounds correct, but there are a great many aspects of the English language where the correct method sounds wrong and vice versa. The sentence "Who cares about ... ?" implies it is expecting an answer to the variety of 'which singular person', not 'which individuals'. It is also mostly used rhetorically.
The problem is that in the case of Gran's question, the intention of the word 'who' is not directly clarified. Does it expect an answer in the form of a singular person/singular group, or perhaps a plural title or a listing of individuals? In an ambiguous situation such as this one, the question should be geared towards its expected answer. Given that it used 'mathematicians' as its example, I take it to mean that it's looking for a plural answer. If one were to take out "besides mathematicians" and expect 'mathematicians' as the answer, the answer would be "Mathematicians care." Therefore, if such an answer is expected, the question should also be phrased correctly. However, this is not often given much consideration, as English is a highly convoluted language and laziness is very common among its speakers. I am quite guilty of this myself. 
Consider the question from this perspective: "Who are those who care about ... ?" More specifically, "Besides mathematicians, who are those who care about Boolean rings?" This is perhaps a sufficiently correct method in which to ask the question while providing clear implication as to the format of the expected answer.
Then again, if the question originated from the Internet, my expectations of correctness would be futile. 
You are absolutely correct in the sense that asking "Who care about ... ?" sounds wrong. It certainly does. Hearing it irks me, regardless of how correct it may be. However, sounding wrong does not mean that it is technically incorrect.
I have provided a lot of ESL instruction over the years and I am of the belief that ESL students should learn the most correct manner of usage, rather than the most commonly believed-to-be-correct manner of usage. It's an age-old argument as to which is the better method to teach and there are probably an equal number of people on each side. I personally do not subscribe to the idea that a language should be taught in an incorrect manner, even if it is easier to learn and will allow the speaker to "sound more fluent".
Technically, "who care about ... " is correct when talking specifically about plural individuals.
Interesting. I wasn't aware of any dialect of English where this would be considered correct.
True, you are speaking to which sounds correct, but there are a great many aspects of the English language where the correct method sounds wrong and vice versa.
My background is in college-level linguistics where the only definition of grammatical is that it sounds correct to a native speaker. Linguists study descriptive grammar (describing what it means to "know" a language) whereas English teachers deal in prescriptive grammar (prescribing the "proper" way to use a language). Linguistics is a big subject and I won't attempt to explain it here.
"Besides mathematicians, who are those who care about Boolean rings?"
FYI, that sentence sounds good to me. The verb "to be" has been conjugated "are" for third person plural, so I must have been mistaken about always conjugating as third person singular ("*Who is those who care?")
UHHHHHHHHHHHHHHH OK
Isn't language fun?
I've always taken satisfaction in using 'correct' English, though I rarely put in the effort to type or speak in any sort of correct manner. While it interests me from an academic perspective, I'm too lazy to maintain it through everyday life. My speech is especially horrible because my thought process is naturally faster than my speech processing. If I'm not mindful of my speech, I tend to omit or combine words when trying to explain complicated topics, at which point it sounds like I'm straying into some foreign language.
So does that answer your question, Gran?
Yes, thank you all for your answers! This was very interesting discussion here.
By the way, the answer to this question is (quoted from: Computer Systems, A Programmer’s Perspective, Bryand and O’Hallaron):
Every time you enjoy the clarity of music recorded on a CD or the quality of video recorded on a DVD you are taking advantage of Boolean rings. These technologies rely on error-correcting codes to reliably retrieve the bits from a disk even when dirt and scratches are present. The mathematical basis for these error-correcting codes is a linear algebra based on Boolean rings.
In German (also by the way 
) we would always say «Who cares about …». Even if the answer is «the pigs» or so.
Granjow
Ah I was wondering what Boolean rings are, as I know when programming, a Boolean is a variable that can be either true or false.
Thanks to SBIzokronus for the fantastic sig!
i'm just making this post to remind myself to read this topic when i have more time (Asaic's post is freaking long)
so, basically just ignore this post
Boolean rings, by the way, are also used in cryptography (GPG/PGP, encryption, everywhere). They are e.g. a collection of numbers, like from 0 to 4, with some operations and special elements defined upon it. Like in this example + would be defined as normal addition modulo 5 (if the number obtained is equal or larger than 5, divide by 5 and take the rest):
2+2=4
2+3=0
4+4=3
and so on. 0 is the neutral element (2+0=2 eg), every element has an inverse element such that you obtain the neutral element again (2+3 = 1+4 = 0+0 = 0 ). And so on. Wikipedia knows more about that. See the definition here. But anyways, this is only interesting if you can make use of it, and I cannot at the moment
They are, however, not even half as complicated as the English language.
Granjow
Boolean rings, by the way, are also used in cryptography (GPG/PGP, encryption, everywhere). They are e.g. a collection of numbers, like from 0 to 4, with some operations and special elements defined upon it. Like in this example + would be defined as normal addition modulo 5 (if the number obtained is equal or larger than 5, divide by 5 and take the rest):
2+2=4
2+3=0
4+4=3
and so on.
Do you mean subtract by 5? Because 5/5=1, and 8/5=1.6; whereas, 5-5=0, and 8-5=3. That would make more sense.
Granjow wrote:
normal addition modulo 5 (if the number obtained is equal or larger than 5, divide by 5 and take the rest)Do you mean subtract by 5?
He was trying to define modulo as "divide and take the rest". The English word for this operation is remainder.
Part two
I know that already.
vs
I already know that.
What is the difference?
And something else; It would be great if you could review this tutorial:
http://granjow.net/grid.html
Not about AC this time though
Granjow