Recently I read this sentence, and I am wondering, what is the function of "so" here?
XYZ is the top provider of high-speed Internet services in the country, or so it claims in its advertisements.
I mean it is not a conjunction, obviously. However, could it be an adverb or even a pronoun? Because the the verb "claim" is a transitive verb, so it needs a pronoun.
Could someone help?
"so" is an anaphoric pronoun (or "pro-sentence") which refers back to the preceding clause and is the object of "claims".
I'd go for so being a connective adverb - anaphoric of course - which here is in combination with the coordinator or. The or-coordinate serves to qualify the advertiser's commitment to the proposition expressed in the first coordinate.
The function of "so" in these contexts is for the writer/speaker to signal that they are not making the statement in the first clause, but transferring that responsibility elsewhere: "It will snow all over the country tomorrow, or so the weather bureau has forecast.". The writer/speaker is not necessarily disagreeing or being skeptical, just using caution.
It is also frequently used in idiomatic form: "This is a great restaurant, or so I'm told / so I've heard.", and also adjectivally: "The so-called Racehorse Scandal is still making the headlines.". If it is over-used it can sound odd (ie, using it where the tag on an event is very well known, and "so-called" is not warranted, such as in: "The so-called Watergate Scandal ...").
