Let P D .X; / be a finite poset that is not a total order. Prove that P contains incomparable elements x and y such that 0 D [ f.x; y/g is a partial order relation. Such a pair of elements is called a critical pair.

Lecture 34 Indeﬁnite Integrals & Net Change Theorem (Section 5.5) Note the connections between antiderivatives and the deﬁnite integral from: Fundamental Theorem of Calculus, part I ▯ x If f is continuous, then f(t)dt is a Fundamental Theorem of Calculus, part II ▯ b f(x)dx = a where Indeﬁnite Integrals Deﬁnite Integrals