"Irrelevant for" vs. "irrelevant to"
Solution 1:
I prefer irrelevant to, but certainly accept irrelevant for:
- Noun phrase: This is irrelevant to (for) the matter at hand
- Gerund: This is irrelevant to (for) resolving the matter at hand
- Personal pronoun: This is irrelevant to (for) me
However, when the complement is preposed, I prefer for over to:
- Noun phrase: For/?to the matter at hand, this is irrelevant
- Gerund: For/??to resolving the matter at hand, this is irrelevant
- Personal pronoun: For/to me, this is irrelevant
—though note that to me in the last sentence means to my mind (To me, this is irrelevant doesn't seem to mean what This is irrelevant to me does)
Solution 2:
Although, mostly, "irrelevant to" is the correct phrase, it is sometimes used interchangeably with "irrelevant for". I couldn't find many examples where "irrelevant for" has been used (and in these examples, "irrelevant for" can be conveniently replaced by "irrelevant to").