A simple example on "true on parts, false on parts"

Draw two points A and B, and a circle c centered at A and passing through B. Now trace a line f passing through A and B and consider the intersection points, C and D, of the circle c with the line f . Ask about the equality between B and C.[br][br]This is a very simple example of automated reasoning in GeoGebra that shows a conflict and explains why some statements are neither true nor false.
Use the Relation tool to ask about B and C
Are you expected some different answer?
Why is this statement considered as "true on parts, false on parts"?[br]Think about how points C and D are constructed.
– Zoltán Kovács, M. Pilar Vélez

Information: A simple example on "true on parts, false on parts"