Install acl2-infix by entering the following commands in the terminal:
sudo apt update sudo apt install acl2-infix
Computational Logic for Applicative Common Lisp: infix interface
ACL2 is both a programming language in which you can model computer systems and a tool to help you prove properties of those models. . This package contains utilities and libraries to access ACL2 via an infix notation similar to that used in many non-lisp programming languages.