Exercise 7.17

According to some political pundits, a person who is radical ($R$) is electable ($E$) if he/she is conservative ($C$), but otherwise is not electable.

1. Which of the following are correct representations of this assertion?

1. $(R\land E)\iff C$

2. $R{:\;{\Rightarrow}:\;}(E\iff C)$

3. $R{:\;{\Rightarrow}:\;}((C{:\;{\Rightarrow}:\;}E) \lor \lnot E)$

2. Which of the sentences in (a) can be expressed in Horn form?