Logic gate problem, only 2 inverters allowed... unsolvable???

[delta595]

I was having a casual chat with one of my professors and he presented me with a problem that after 4 hours of attempting I believe is unsolvable. The set up is pretty simple.

You have 3 inputs x,y,z that go into a system, the output is ~x,~y,~z. However you are only allowed to use 2 inverters gates in the system.

I can get very close using a single xor and a not gate and i need one more.

Basically I want to know if this problem is solvable, I have looked into quantum gates to see if there is some way to hybrid this but my knowledge of them is limited.

 

[LiteYear]

You need 3 outputs (none of which are equal to the inputs) with only 2 gates? Seems to me the answer would have to be quite unusual.

What exactly are "inverters gates"? Your example includes an XOR and a NOT gate, so I'm not sure what the restriction is.

It would seem a little cruel of your professor to pose a question that is not solvable...

 

[delta595]

He said I am allowed to use as many gates as i want, but only two can invert signals. So an inverter is a; not, nand, nor type gate. Also a xor gate can be built using a single nand so it is included as a inverter.

 

[IRstuff]

http://www.eetimes.com/design/progr...T-gates-and-no-XOR-gates--Part-1?pageNumber=1

TTFN
faq731-376