# Re: ?? Functional Dependency Question ??

From: paul c <toledobythesea_at_oohay.ac>

Date: Tue, 21 Oct 2008 12:15:22 GMT

Message-ID: <uJjLk.2870$fF3.408_at_edtnps83>

Date: Tue, 21 Oct 2008 12:15:22 GMT

Message-ID: <uJjLk.2870$fF3.408_at_edtnps83>

David BL wrote:

...

*> RTP: (X->A)(Y->B) -> XY->AB
**>
*

> (X->A)(Y->B) : premise

*> X->A, Y->B : conjunction elimination
**> XY : premise
**> X,Y : conjunction elimination
**> A : modus ponens on X,X->A
**> B : modus ponens on Y,Y->B
**> AB : conjunction introduction
**> XY->AB : conditional proof
**> (X->A)(Y->B) -> XY->AB : conditional proof
**>
*

I can see that the second step is eliminating a "conjunction" but the fourth step doesn't seem to me to involve a conjunction. Received on Tue Oct 21 2008 - 14:15:22 CEST