# The properity of $\mathbb{R}^4$ that has infinitely many differential structures is related to Yang-Mills field?

I heard a saying that $\mathbb{R}^4$ having infinitely many differential structures which are not diffeomorphic to each other has a relationship with Yang-Mills field. Does anyone can explain it, and give me some references.

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Relevant : 1. Donaldson theory 2. Seiberg-Witten invariants –  user10001 May 4 at 8:02
@user10001 Can you speak more explicitly? Thanks! –  user34669 May 4 at 11:48