According to Wolfram Mathworld,
Two planes that do not intersect are said to be parallel.
So two identical planes are not considered to be parallel? That seems strange to me.
I guess my question is similar to this: Is a line parallel with itself?
According to Wolfram Mathworld,
Two planes that do not intersect are said to be parallel.
So two identical planes are not considered to be parallel? That seems strange to me.
I guess my question is similar to this: Is a line parallel with itself?
If the planes are the same, then they are parallel. If the do not intersect at all, they are parallel. The real way to define planes being parallel would be if their normal vectors are parallel.