Def as @ bs == Case of as; nil  bs ; a.as'  [a / (as' @ bs)]  (recursive)

is mentioned

In prior sections: list 1 mb list 1 mb list 2 mb event system 1 mb event system 3 mb event system 4

Try larger context: EventSystems IF YOU CAN SEE THIS go to /sfa/Nuprl/Shared/Xindentation_hack_doc.html