3 ms·

I’m confused by the three sets in the second figure: A, B and A-B. At first I took it to mean that there was some transformation of sets A and B that resulted i

by adolph 2y ago

I’m confused by the three sets in the second figure: A, B and A-B. At first I took it to mean that there was some transformation of sets A and B that resulted in shape A-B. After rereading a couple times I think A-B is supposed to represent an intersection of some other sets A and B, not the two present to the left, and the significance of this intersection is that it overlaps the origin or 0,0. Is that right? Hope this feedback is helpful.

bonzini 2y ago
It's literally a difference of coordinates, not an intersection. Take all pairs of points in the (filled) polygons A and B, subtract their coordinates, and include the difference in A-B. If there is an intersection, there is at least one pair that consists of the same point twice; the difference of coordinates will be (0,0) and therefore, if there is an intersection then A-B contains the origin.