Monadic Predicate Logic - Hard Question

Symbolize the following:

Although some mean elves will bite even though not provoked, neither Bruce nor Carrie will bite unless provoked.

Symbolization attempt:

$\displaystyle \exists x ((Gx \wedge Hx) \wedge (Ix \wedge \neg Jx)) \wedge (\neg (Ib \vee Ic) \vee (Jb \vee Jc)) $

Symbolization Key:

F{1} {1} is friendly.

G{1} {1} is mean.

H{1} {1} is an elf.

I{1} {1} will bite.

J{1} {1} is provoked.

b Bruce

c Carrie

Apparently my answer is wrong, but I don't know why. Any help would be appreciated.

Re: Monadic Predicate Logic - Hard Question

whats correct answer ? is it given ? to me your answer looks fine

Re: Monadic Predicate Logic - Hard Question

Quote:

Originally Posted by

**RogueDemon** $\displaystyle \exists x ((Gx \wedge Hx) \wedge (Ix \wedge \neg Jx)) \wedge (\neg (Ib \vee Ic) \vee (Jb \vee Jc)) $

The second part of this formula is true if Bruce was provoked, but it was Carrie who bit, while the original sentence presumably disallows this.

Re: Monadic Predicate Logic - Hard Question

ahh i see

the second part should be

$\displaystyle (I_b \Rightarrow J_b)\wedge(I_c \Rightarrow J_c)$

right makarov ?

Re: Monadic Predicate Logic - Hard Question

Re: Monadic Predicate Logic - Hard Question

Thank you! I've been stuck on this problem and another for days. :/