Homework Help: Discrete Math Exam Question

1. Feb 21, 2012

Shackleford

"For the router to support the new address space it is necessary that the latest software release be installed."

I said

Q: The latest software released be installed
R: The router to support the new address space.

I interpreted this as Q is necessary for R, therefore R => Q.

The professor has

Let Q be The router supports the new address space.
Let R be The latest software release is installed.

R => Q

Am I interpreting the sentence incorrectly?

2. Feb 21, 2012

Dick

Yeah, I'm afraid so. If I read that in a software release statement I might think the latest software release would support the new address space. But it doesn't really say that. It just says that an older release WILL NOT support the new address space. It doesn't really promise that the new one will. Nice marketing ploy.

3. Feb 21, 2012

Shackleford

It's saying "that the latest software release be installed" is necessary "for the router to support the new address space."

"a necessary condition for p is q"

"q is necessary for p"

P => Q

4. Feb 22, 2012

Dick

No, if q is necessary for p then p->q.

5. Feb 22, 2012

Shackleford

That's what I just typed.

P => Q

6. Feb 22, 2012

Dick

Sure, sorry. Wow, that was fast.