The command ’A=(1,2,3)’ generates a free point at the position (1|2|3). As the comma is used as a separator, the decimal-separator is the point (’.’) for all languages!
The command ’v=(1,2,3)” generates a vektor . The difference to generating a point is that the name is lowercase.
For points, the arguments can be expressions (one expression each for the x, y and z-coordinate). If you wan to generate vectors from expressions, you will have to use the vector-command.