Positions and Translations
Now that we have defined coordinate frame let's say r, we can define other constructs like points, vectors, etc with respect to the defined coordinate frame.
Like a point in 3D space be defined as a vector from the origin of the coordinate frame to that point.
We say that point p's coordinates are expressed as in the coordinate frame r. The x_r, y_r, and z_r are the projections of the point p onto the x, y, and z axes of the coordinate frame r, respectively.
Translation/Displacement between points
We can translation/displacement represent it as: