update README & add sponsor

README.md

@@ -1,14 +1,13 @@
 # Arithmetization
 
-Formalization of weak arithmetic and arithmetization of metamathematics. This project depends on [lean4-logic](https://github.com/iehality/lean4-logic/tree/master).
-
-https://iehality.github.io/Arithmetization/
+Formalization of weak arithmetic and arithmetization of metamathematics. This project depends on [Foundation](https://github.com/FormalizedFormalLogic/Foundation).
 
 ## Table of Contents
 - [Arithmetization](#arithmetization)
   - [Table of Contents](#table-of-contents)
   - [Structure](#structure)
   - [References](#references)
+  - [Sponsor](#sponsor)
 
 ## Structure
 
@@ -23,3 +22,11 @@ https://iehality.github.io/Arithmetization/
 ## References
 - P. Hájek, P. Pudlák, Metamathematics of First-Order Arithmetic
 - S. Cook, P. Nguyen, Logical Foundations of Proof Complexity
+
+## Sponsor
+
+This project is supported by [Proxima Technology].
+
+[<img height="60" src="https://raw.githubusercontent.com/FormalizedFormalLogic/.github/refs/heads/main/profile/proxima_technology.svg">][Proxima Technology]
+
+[Proxima Technology]: https://proxima-ai-tech.com/