Why is が used this way in this sentence with 好き?


> せんぱいが好きな食べ物は、なんですか？

I come across this sentence in a web novel, I think it is supposed to be
せんぱいの好きな食べ物は、なんですか？Why is せんぱい marked with が here? Is there a different use of
the word すき other than the comman usage: "先輩は食べ物が好きだ" that mark the person
other than the object being described as favourite? Is it an example of the
usage "in love (with)" in the EN-JP dictionary?




With adjectives like 好き it is possible to say the following

> [sentence 1] りんごがすきです

> [sentence 2] わたしがすきです

**Sentence 1** should be relatively easy to understand

> _Someone_ likes apples.

**Sentence 2** isn't particularly clear when completely divorced from context.

It could mean,

> _Someone_ likes me

I would say that _without_ any further context, this is the default reading.

But it could also mean,

> _I_ like _something_.

There's a lot of discussion on this site about the difference between は and が
in this sort of context. I'll leave that discussion aside except to say that
as a stand alone sentence

> わたしがすきです

Either sounds like _I_ am liked by someone or _I_ am the sole individual
within _some group_ who likes something.

* * *

But, we don't have a stand-alone sentence here.

We have instead

> せんぱいが好きな食べ物は、なんですか

せんぱいが好きな is a relative clause modifying 食べ物. Since _foods_ typically don't
have a preference for who's going to eat them (unless your in some strange
alternate universe of anime, sci-fi, etc), the most natural way to construe
this is that 食べ物 is what is being _liked_.

That means that the relative clause

> せんぱいが好きな

functions much like **sentence 2** above in the sense where it is せんぱい is the
one who is liking something.

_But,_ there is one important caveat here. The は-が distinction I mentioned
above is null here. That's because は as the topic marker cannot be embedded in
a relative clause (when は is found in a subordinate clause, then は is not
marking the topic but usually functioning _contrastively_ ).

So this が in the relative clause marks the _subject_ who _likes_ some kind of
food. Unlike **sentence 2** above, in a relative clause, the reading is
neutral: that is, nothing is to be construed as _せんぱい_ being the only
individual who likes something.

* * *

You could indeed say

> せんぱいの好きな食べ物は、なんですか

But if you're thinking this の is a possessive marker indicating

> せんぱいの食べ物

then you are unfortunately mistaken. A native speaker is not naturally
inclined to hear it like this. That is because の can be used in relative
clauses (under special conditions which apply here) to stand in for the
subject marker が.

* * *

For details on subtopics I've brought up:

  * See this [question for が as an exhaustive listing marker](https://japanese.stackexchange.com/a/72751/4875)

  * See this [question for は vs が in relative clauses](https://japanese.stackexchange.com/a/54693/4875)

  * See this [question for when の can be substituted for the subject marker が in relative clauses](https://japanese.stackexchange.com/a/12829/4875)

