A colleague of mine corrected the following sentence in a text I had written:
A handful of iterations was generally enough for convergence.
According to her it should be:
A handful of iterations were generally enough for convergence.
I am, however, confident that my original usage was correct, but I am unsure how I should motivate this.
EDIT: What made me think it was singular was not "a handful of". I thought it would be correct to say Five iterations is enough. because it is a statement about the number of iterations rather than the iterations themselves. When googling to find an answer I found a television series called Eight Is Enough. Is that correct because the noun is left out? Compare the sentences: Three friends are ideal. and Three friends is ideal. I would have thought that the first sentence means that there are three persons who are ideal friends, while the second sentence means that three is the ideal number of friends to have. But maybe my intuition is really off here.
EDIT2: Here it is stated that:
*Subjects expressing periods of time, amounts of money, or quantities may take either singular or plural verbs depending on whether represent a total amount or a number of individual units. For example, "Four weeks is not enough vacation time" and "Two days have passed since I asked for your response."
Isn't the first example here quite similar to mine?
Best Answer
Edit 2
After your edit, the question becomes one of whether a group of things can be taken as a collective singular, such as in this question, which asks such things as whether a dozen somethings “is” enough.
The answer is that it can be singular if you are thinking of it as one thing as a whole, just as in:
In that sort of sentence, you get agreement like this:
It really just depends on what you’re trying to say, and how you’re trying to say it. If you want to say that five matches is more than you can handle or that three olives is too many for a martini, then yes, sure you can.
But normally plural things take plural agreement — see the ngram below, which shows that a handful of men will usually take plural agreement because men is plural, no matter the status of the a handful of premodifer.
It is only when you logically group them as one thing that they take singular agreement. By doing so, that is what you are conveying.
But perhaps your friend does not like it when the council is decided on something, as opposed to when they are divided. :)
Original Answer
Your friend is right, and you are wrong.
When you have a premodifier like a lot of, a number of, or a handful of preceding the head noun, the verb continues to agree with that head noun, instead of with the notionally singular a lot, a number, a handful, which functions more like a red herring than anything else.
Ok, seriously, these premodifiers are really acting like adjectives, not like prepositional phrases. That means the head noun remains the head noun, and there is no change to agreement:
As opposed to something like:
Edit
Although there is a bit of room for variation here, depending on just what the writer is thinking, there is a clear dominance of the plural continuing to be used after a handful of men in this Google N-Gram chart: