The Hodge conjecture is difficult because elaborate submanifolds are really rigid objects (considering that They're described by polynomials). In reality, it is quite challenging to build elaborate submanifolds, and you will discover very few of these. Proving that submanifolds exist with out setting up them (a really handy sort of https://socialislife.com/story4796002/the-best-side-of-bos138-slot