Green's Open Problems #96

### What is the conjecture
https://people.maths.ox.ac.uk/greenbj/papers/open-problems.pdf#problem.96

Is every set $\Lambda \subset \mathbb{Z}$ either a Sidon set, or a set of analyticity?

### [AMS categories](https://github.com/google-deepmind/formal-conjectures/labels?q=ams-)

* ams-11

### Choose either option
- [ ] I plan on adding this conjecture to the repository
- [x] This issue is up for grabs: I would like to see this conjecture added by somebody else

Read problem 96 in the linked open-problems.pdf and inspect the formal-conjectures repository's existing Lean conjectures for the expected structure and contribution process. Done means the stated conjecture is added as a Lean formalization with the repository's checks passing; the issue names no specific file or test entry point.

Written by the indexing model from the issue text.