Some definitions of interest.
nat_plus	Def  == {i:| 0<i }
	Thm*   Type
qmul	Def a *q b == (a.numb.num)/(a.denb.den)
	Thm* p,q:. p *q q
qdenom	Def q.den == 2of(q)
	Thm* q:. q.den
qnum	Def p/q == <p,q>
	Thm* n:, d:. n/d
qnumer	Def q.num == 1of(q)
	Thm* q:. q.num

About: IF YOU CAN SEE THIS go to /sfa/Nuprl/Shared/Xindentation_hack_doc.html