(ft (peters-buy) (buy peters _what) _what)

(hn (buy _broker _prod)
    (want (customer _broker) _prod)
    (deal _prod (cost _prod) (benefit _prod)) )

(hn (deal _prod _cost _benefit)
    (>= _benefit _cost) )

(hn (want miller stock1))
(hn (want miller stock2))
(hn (want fuller stock3))

(ft (customer peters)
    miller )
(ft (customer peters)
    fuller )

(ft (cost stock1)
    165 )
(ft (cost stock2)
    130 )
(ft (cost stock3)
    175 )

(ft (benefit stock1)
    160 )
(ft (benefit stock2)
    130 )
(ft (benefit stock3)
    180 )