:: deftheorem Def444 defines Helpme FINANCE6:def 23 :
for d, n being Nat
for jpi being pricefunction
for phi being Real_Sequence holds
( ( n = 0 implies Helpme (phi,jpi,n,d) = - (BuyPortfolio (phi,jpi,d)) ) & ( not n = 0 implies Helpme (phi,jpi,n,d) = phi . n ) );