It's a bold statement to call something a Prolog successor! Are you aiming for a general purpose logic programming language like Prolog, or targeting the use case of querying knowledge bases?

One of the draws to Prolog is its immensely simple syntax: A.R:B = true in your case would be represented as simply r(A, B).

It looks like you've elevated some set theory properties to syntax, and have added some neat sugar over chained relations. Have you found areas where this really shines as compared to writing more standard Prolog/Datalog queries? I'm afraid I couldn't see many examples on first look at your Github.