Which of the following sentences are correct?
Effective algorithms for concurrent programming is the main subject of of investigation in this note.
Effective algorithms for concurrent programming are the main subject of of investigation in this note.
My confusion is that "Effective algorithms" is plural, but "Effective algorithms for concurrent programming" as a whole is the subject of investigation.
In https://en.wikipedia.org/wiki/Copula_(linguistics) it is stated that "the copula normally agrees with the preceding phrase even if it is not logically the subject". But I still have doubts about the above sentences.