Can anyone give me an example of non-"vectors"? Thank.

The set of all natural numbers is not a vector space.

@WALL-E: Correct. For instance, there is not even an additive identity! (I.e., no number "0" such that 0+x=x+0=x.)

Can anyone give me an example of non-"vectors"? Thank.

The set of all natural numbers is not a vector space.

@WALL-E: Correct. For instance, there is not even an additive identity! (I.e., no number "0" such that 0+x=x+0=x.)