3 or 4?

Stream: lean4

[Ignat Insarov]

I am new to the Lean community. I was made aware that Lean 3 and Lean 4 are significantly different. How can I educate myself on these differences and make an informed decision as to which one to go with?

[Bryan Gin-ge Chen]

Let me quote from another recent thread:
Anne Baanen said:

Welcome! At the moment, the Lean mathematics community is mostly still focussed on Lean 3, although we are hard at work at moving everything to Lean 4. So if you want to do mathematics in Lean, then I would recommend the Lean 3 (community edition). If you want to program in Lean, and have your programs run quickly, then Lean 4 would be a better choice since its programming capabilities are much better.

Most of the learning material is focused on Lean 3 at the moment. Our page for those resources is here: https://leanprover-community.github.io/learn.html