Talk:Conjunction and Implication

The second part of each of these don't strike me as necessarily true.
I'm probably wrong since I don't have time to look in detail/try to prove them now.
Explanation/proof of at least one of them would be appreciated. --cynic 22:35, 1 August 2008 (UTC)

Use truth tables

You may be correct! I'll go away and check them properly, sorry, I've had one or two other things to do the last few days.

Rather than use natural deduction, you can always use a truth table method, which should be adequate. I do have the proofs for these but I haven't got round to putting them up yet. Many thanks for your interest.--Matt Westwood 09:39, 2 August 2008 (UTC)

Yep checked em all

... they're all sound, as far as I can tell, but all (bar one) use the LEM to prove their converses.--Matt Westwood 21:36, 3 August 2008 (UTC)