### 11.16.14 Check if elements are conjugates: is_conjugate

The is_conjugate is a Boolean function which takes as arguments one of the following:

- A circle followed by two more arguments, each of which is a point or a line.
  In this case, is_conjugate returns 1 if the last two arguments are conjugate with respect to the circle, it returns 0 otherwise.
  Input:
  is_conjugate(circle(0,1+i),point(1-i), point(3+i))
  Output:
  1
  Input:
  is_conjugate(circle(0,1),point((1+i)/2), line(1+i,2))
  Output:
  1
  Input:
  is_conjugate(circle(0,1), line(1+i,2), line((1+i)/2,0))
  Output:
  1
- Two lines or two points, followed by two more arguments, each of which is a point or a line.
  In this case, is_conjugate returns 1 if the last two arguments are conjugate with respect to the first two arguments, it returns 0 otherwise.
  Input:
  is_conjugate(point(1+i),point(3+i),point(i),point(3/2+i))
  Output:
  1
  Input:
  is_conjugate(line(0,1+i),line(2,3+i),line(3,4+i),line(3/2,5/2+i))
  Output:
  1