Def  pq == if p q else false fi

is mentioned by

Def  i  j < k == (ij)(j<k)

[lelt_int]

In prior sections: bool 1

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