as·ser·tion / əˈsərshən/ • n. a confident and forceful statement of fact or belief: his assertion that his father had deserted the family. ∎  the action of stating something or exercising authority confidently and forcefully: the assertion of his legal rights.

assertion A Boolean formula whose value is claimed to be true. The following are all examples: 4 + 5 = 9 4 is even and 5 is odd x is even or y is odd x – y > 15 for all relevant i, x[i] < x[i+1]

The last assertion states that the array x is sorted into ascending order, with no repeated values.

Assertions are employed extensively in proofs of program correctness, where they are used to characterize program states.

assertion (ă-ser-shŏn) n. the skill to communicate positively in order to press one's own claims, rights, or opinions.