Union
The union used in set theory is defined in terms of a logical disjunction: x ∈ A ∪ B if and only if (x ∈ A) ∨ (x ∈ B). Because of this, logical disjunction satisfies many of the same identities as set-theoretic union, such as associativity, commutativity, distributivity, and de Morgan's laws.
Read more about this topic: Logical Disjunction
Famous quotes containing the word union:
“What should concern Massachusetts is not the Nebraska Bill, nor the Fugitive Slave Bill, but her own slaveholding and servility. Let the State dissolve her union with the slaveholder.... Let each inhabitant of the State dissolve his union with her, as long as she delays to do her duty.”
—Henry David Thoreau (1817–1862)
“The rage for road building is beneficent for America, where vast distance is so main a consideration in our domestic politics and trade, inasmuch as the great political promise of the invention is to hold the Union staunch, whose days already seem numbered by the mere inconvenience of transporting representatives, judges and officers across such tedious distances of land and water.”
—Ralph Waldo Emerson (1803–1882)
“If the Union is now dissolved it does not prove that the experiment of popular government is a failure.... But the experiment of uniting free states and slaveholding states in one nation is, perhaps, a failure.... There probably is an “irrepressible conflict” between freedom and slavery. It may as well be admitted, and our new relations may as be formed with that as an admitted fact.”
—Rutherford Birchard Hayes (1822–1893)