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proof, in mathematics

(Encyclopedia)proof, in mathematics, finite sequence of propositions each of which is either an axiom or follows from preceding propositions by one of the rules of logical inference (see symbolic logic). Mathematic...

proof, in printing

(Encyclopedia)proof, in printing, a trial impression for inspection. Proofreading is the inspection and marking of proof for correction of errors and imperfections. Proofreaders' marks are included in dictionaries....

Proteus, in astronomy

(Encyclopedia)Proteus prōˈtēəs, –tyo͞os [key], in astronomy, one of the natural satellites, or moons, of Neptune. ...

period, in grammar

(Encyclopedia)period: see punctuation.

period, in physics

(Encyclopedia)period, in physics: see harmonic motion; wave. ...

periwinkle, in botany

(Encyclopedia)periwinkle, in botany: see dogbane. ...

periwinkle, in zoology

(Encyclopedia)periwinkle, any of a group of marine gastropod mollusks having conical, spiral shells. Periwinkles feed on algae and seaweed. They are found at the water's edge; out of water, they resist drying by cl...

Perseus, in astronomy

(Encyclopedia)Perseus, in astronomy, northern constellation lying E of Cassiopeia and N of Taurus. It contains the bright star Mirfak (Alpha Persei) and Algol (Beta Persei), a visible variable star of the type know...

ring, in astronomy

(Encyclopedia)ring, in astronomy, relatively thin band of rocks and dust and ice particles that orbit around a planet in the planet's equatorial plane. All four of the giant planets in the solar system—Jupiter, S...

Randolph, Asa Philip

(Encyclopedia)Randolph, Asa Philip, 1889–1979, U.S. labor leader, b. Crescent City, Fla., attended the College of the City of New York. As a writer and editor of the black magazine The Messenger, which he helped ...