One-period call price bounds
= One-period call price bounds
{title2=$(s-b)^+\leq c\leq s$}
A positive <one-period martingale deflator> applied to $C=(S-B)^+$ gives $(s-b)^+\leq c\leq s$. If both strict payoff regions $S>B$ and $S<B$ have positive probability, then $c>0$ and $c-(s-b)>0$, proving the strict lower bound. No normalization of the positive pricing variable is needed.