Writing a paper with Edward Witten is an interesting process.
They often have a dispute over some issues that they debate for quite some time.
It's a matter of differing perspectives.
Edward Witten often approaches issues from the foundation of idle theory. He is a hundred percent in favor of the 'Particle Boundary Theory' since the most basic energy unit in it is very similar to a string.
Zhao Yi has always defined the energy unit as 'source', meaning the most original, vague and unclear. With current science unable to verify this, it serves merely as a definition.
Edward Witten, on the other hand, believes that the string is crucial to the 'Particle Boundary Theory'. He views the energy unit as a string, or perhaps as a 'three-dimensional universe projection (avatar)' of a string.
Of course, Zhao Yi won't accept this.