"There isn't either oil or vinegar in the cupboard."
Translation:Il n'y a ni huile ni vinaigre dans le placard.
That's a good question, I never thought about that.
"Il n'y a ni d'huile, ni de vinaigre" also sounds perfectly fine to me and has exactly the same meaning as far as I can tell. That might be a bit easier to remember and a bit more regular for a foreign learner I suppose, since it matches the negative construct: "Il n'y a pas d'huile, il n'y a pas de vinaigre, il n'y a ni d'huile, ni de vinaigre".
"Il n'y a pas l'huile, ni le vinaigre" also works, but that's a different sentence: "there isn't either the oil, or the vinegar..."
'When using ni, you omit the article after ni, unless you're talking about general things and using le, la, l', les.' https://french.kwiziq.com/revision/grammar/how-to-use-ne-ni-ni-neither-nor-negation#:~:text=When%20using%20ni%2C%20you%20omit,brothers%20nor%20sisters%20nor%20cousins.
Thanks for sharing this, it's very helpful! I am still wondering why the use of definite articles wouldn't work in this instance (ni l'huile ni le vinaigre).
This link gives the example:
*Tu aimes le fromage ? - Je n'aime ni le fromage ni le lait.
*(Do you like cheese ? - I like neither cheese nor milk.)
Isn't the sentence about no oil/vinegar in the cupboard also making a general statement?
Not the way I use it. I mean there isn't either one or the other, there isn't either one of them. Plainly, "not either" is exactly the same as "neither". I think the vast majority of English speakers worldwide agree with me, and so do all the grammar/usage references.
I have already linked to several grammar resources. Below are two additional links. I notice that not even one reference has been shown to dispute this. I don't think you'll be able to find expert support either.
"Neither goes before singular countable nouns. We use it to say ‘not either’ in relation to two things. https://dictionary.cambridge.org/us/grammar/british-grammar/neither-neither-nor-and-not-either_2
"When used as an adjective either means "one or the other of two people or things," and neither means "not one or the other of two people or things." In other words, neither means "not either." [...] "You may borrow neither book. [=you may not borrow one and you may not borrow the other of the two books; you may not borrow either book]" https://www.learnersdictionary.com/qa/The-Difference-Between-Neither-and-Either
I agree completely. "There is not either oil or vinegar," means that they are both absent. The inverse, "There is either oil or vinegar," means one or the other is present (or maybe both). To say that only one of them is absent but you're not sure which, you would have to say "There is either no oil or no vinegar in the cupboard."