Who Cites exteq?
exteq	Def  A =ext B == (x:A. x  B) & (x:B. x  A)

Syntax:

A =ext B

has structure:

exteq(A; B)

About: IF YOU CAN SEE THIS go to http://www.cs.cornell.edu/Info/People/sfa/Nuprl/Shared/Xindentation_hack_doc.html