- Statements with “for all” and “there exist” in them are called quantified statements. “For all”, written with the symbol ∀, is called the Universal Quantifier and and “There Exists” , written with the symbol ∃, is called the Existential Quantifier. A quantifier turns a predicate such as “x is greater than 7” into a statement that can be true for false. For instance, “For all x, x is greater than 7” is false as 2 is not greater than 7, but “There Exists an x such that x is greater than 7” is true as 8 is greater than 7.
- Robert Burnham Jr. (Wikipedia)
Robert Burnham Jr. (June 16, 1931 – March 20, 1993) was an American astronomer, best known for writing the classic three-volume Burnham’s Celestial Handbook. He discovered numerous asteroids, including the Mars crossing asteroid 3397 Leyla, and six comets.