I found something that boggles me ( I'm really a beginner in symbolic logic, so maybe it's very trivial).
I was practicing with truth-tables, and I found that:
"p->p" is a tautology
"(p->p)->p" is not a tautology.
I decided to go further, and:
- "((p->p)->p)->p" is again a tautology, but
4."(((p->p)->p)->p)-> p" is not, and it keeps alternating.
I checked with an online logic calculator, and it seems correct.
Now, do you know why is that? Is there any particular reason for this pattern?