Prove that the Digraph of a partial order has no cycle of length greater than 1.

Assume that there exists a cycle of length n ≥ 2 in the digraph of a partial order ≤ on a set A. This entails that there are n distinct elements a₁ , a₂ , a₃ , ..., an like that a₁ ≤ a₂ , a2 ≤ a₃ , ..., an-1 ≤ a_n and an ≤ a₁ . Applying the transitivity n-1 times on a₁ ≤ a₂ , a₂ ≤ a₃ , ..., a_n-1 ≤ a_n , we get a1 ≤ an .As relation ≤ is anti-symmetric a1 ≤ a_n and a_n ≤ a₁ together entails that a₁ = a_n . This is contrary to the fact that all a_1, a₂, a₃... a_n are distinct. So, our assumption that there is a cycle of length n ≥ 2 in the digraph of a partial order relation is wrong.