# Function with no output for a given set of vales

#### Code

Joined Nov 29, 2005
3
Hey

if function has no output for encoded numbers above a given number is there anything special when representing the algebraic expression?

Example "1 if even, 0 otherwise.No output above 2."

| X Y
0 .. | 1
1 .. | 0
2 .. | 1
3 .. | x

So is this as simple as

Function = X'Y' + XY'

or is there anything else?

Thank.

#### aac

Joined Jun 13, 2005
35
Originally posted by Code@Dec 4 2005, 08:27 PM
Hey

if function has no output for encoded numbers above a given number is there anything special when representing the algebraic expression?

Example "1 if even, 0 otherwise.No output above 2."

| X Y
0 .. | 1
1 .. | 0
2 .. | 1
3 .. | x

So is this as simple as

Function = X'Y' + XY'

or is there anything else?

Thank.
[post=12185]Quoted post[/post]​
Yes, having combinations that are unspecified can allow some simplification. If there in nothing greater than 2, we can assign anything we want for the other numbers. this is usually refered to as a don't care. Since we dont care, we would assign 3 to be 0. This would let the function simplify to "Function = Y'.