mini-kanren what is the difference between cond-a cond-u and cond-e?

Question

I have tried to use an implementation of mini-kanren in clojure. But been struggling to understand the difference between cond-a cond-u and cond-e. I seem to be quite clear

Answer 1

cond-e gives every answer from all branches that succeed

cond-i gives every answer but interleaves them.

cond-a only gives the answers from the first successful branch

cond-u only gives the first answer from the first successful branch

Answer 2

I was just trying to get my head around these matters. There's a shortified scheme implementation Sokuza-kanren with a few comments, I'll read it tonight.