As with the case with Duke University's calendar, it is also common for there to be two months that differ due to the short number of days. In the case of Duke, June and July are slightly adjusted so the fiscal year can always begin on July 1 and end on June 30.
Let's review. A postulate is a statement accepted to be true without proof. Some common algebraic properties are also postulates and deal with the four operations: addition, subtraction, multiplication, and division. Other true statements are geometric postulates and include the ruler, angle addition, and segment addition postulates.
The parallel postulate. The fifth postulate in Euclid's Elements can be rephrased as. The postulate is not true in 3D, but in 2D it seems to be a valid statement. Considering the importance of postulates however, a seemingly valid statement is not good enough. Exactly one line through the red point is parallel to the thick white line.