Pietro Cataldi

Italian mathematician

** Date of Birth: **15-Apr-1552

** Place of Birth: **Bologna, Emilia-Romagna, Italy

**Date of Death: **11-Feb-1626

**Profession: **mathematician, university teacher

**Zodiac Sign: **Aries

- Pietro Antonio Cataldi (15 April 1548, Bologna â€“ 11 February 1626, Bologna) was an Italian mathematician.
- A citizen of Bologna, he taught mathematics and astronomy and also worked on military problems.
- His work included the development of continued fractions and a method for their representation.
- He was one of many mathematicians who attempted to prove Euclid's fifth postulate.
- Cataldi discovered the sixth and seventh perfect numbers by 1588.
- His discovery of the 6th, that corresponding to p=17 in the formula Mp=2p-1, exploded a many-times repeated number-theoretical myth that the perfect numbers had units digits that invariably alternated between 6 and 8.
- (Until Cataldi, 19 authors going back to Nicomachus are reported to have made the claim, with a few more repeating this afterward, according to L.E.Dickson's History of the Theory of Numbers).
- Cataldi's discovery of the 7th (for p=19) held the record for the largest known prime for almost two centuries, until Leonhard Euler discovered that 231 - 1 was the eighth Mersenne prime.
- Although Cataldi incorrectly claimed that p=23, 29, 31 and 37 all also generate Mersenne primes (and perfect numbers), his text's clear demonstration shows that he had genuinely established primality through p=19.

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