Def True == 0  

is mentioned by

Thm* L:MsgA List. ma-is-empty((L))  reduce(M,x. ma-is-empty(M) & x;True;L)

[assert-ma-join-list-is-empty]

In prior sections: core mb list 1 mb event system 4 bool 1

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