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\subsection*{Answer}

Substitute \,$<<\ov{B}>>_{\ov{w}}$\, for $C$, \,$\TRUE$\, for $\mathcal{N}$, and $I$ for both
$P$ and $F$.  Show that the first and fourth hypotheses of WF2a are
then tautologies, and the remaining hypotheses and the conclusion are
equivalent to the corresponding formulas of WF2s.
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