Q9

[Dyounker]

Does the fact that H move R necessitate G moves S?

[noah]

Does the fact that H move R necessitate G moves S?

Yes. H moving R triggers Gs <--> Hr.

You can get a full write-up of this by looking at the explanations posted here: diagram-t450.html

[jungpark1229]

Hi i had a problem with this question when I took the contrapositives of bi-conditionals.

I mean i realized that Gs <-> Hr, but when I took the contrapositive of this which is Hs/t <-> Gr/t, i couldn't solve question 9.

Should I have not taken contrapositives of biconditionals? But why would taking contrapositive make it difficult to solve any question anyways?

Can any one help?