Os Elementos; Livro 7, definição 2 (Fundamentos da teoria dos números) http://www.euclides.org/menu/elements_esp/07/definicioneslibro7.htm
Frases de Euclides
Data de nascimento: 323 a.C.
Data de falecimento: 285 a.C.
Euclides de Alexandria foi um professor, matemático platónico e escritor grego, muitas vezes referido como o "Pai da Geometria". Além de sua principal obra, Os Elementos, Euclides também escreveu sobre perspectivas, seções cônicas, geometria esférica, teoria dos números e rigor.
A geometria euclidiana é caracterizada pelo espaço euclidiano, imutável, simétrico e geométrico, metáfora do saber na antiguidade clássica e que se manteve incólume no pensamento matemático medieval e renascentista, pois somente nos tempos modernos puderam ser construídos modelos de geometrias não-euclidianas.
Euclides é a versão portuguesa da palavra grega Εὐκλείδης, que significa "Boa Glória".
Said to be a remark made to his servant when a student asked what he would get out of studying geometry.
'threepence' renders τριώβολον "three-obol-piece". This amount increases the sarcasm of Euclid's reply, as it was the standard fee of a Dikastes for attending a court case (μίσθος δικαστικός), thus inverting the role of teacher and pupil to that of accused and juror.
The English translation is by The History of Greek Mathematics by Thomas Little Heath (1921), p. 357 http://books.google.com/books?id=h4JsAAAAMAAJ&pg=PA357#v=onepage&q&f=false. The quote is recorded by Stobaeus' Florilegium iv, 114 ( ed. Teubner 1856 http://www.archive.org/stream/iohannisstobaei00meingoog#page/n598/mode/2up, p. 205; see also here http://laudatortemporisacti.blogspot.ch/2011/04/anecdote-about-euclid.html). Stobaeus attributes the anecdote to Serenus.
Original: (el) Δός αὐτῷ τριώβολον, ἐπειδὴ δεῖ αὐτῷ ἐξ ὧν μανθάνει κερδαίνειν
The earliest published source found on google books that attributes this to Euclid is A Mathematical Journey by Stanley Gudder (1994), p. xv http://books.google.com/books?id=UiOxd2-lfGsC&q=%22mathematical+thoughts%22+euclid#search_anchor. However, many earlier works attribute it to Johannes Kepler, the earliest located being in the piece "The Mathematics of Elementary Chemistry" by Principal J. McIntosh of Fowler Union High School in California, which appeared in School Science and Mathematics, Volume VII ( 1907 http://books.google.com/books?id=kAEUAAAAIAAJ&pg=PR3#v=onepage&q&f=false), p. 383 http://books.google.com/books?id=kAEUAAAAIAAJ&pg=PA383#v=onepage&q&f=false. Neither this nor any other source located gives a source in Kepler's writings, however, and in an earlier source, the 1888 Notes and Queries, Vol V., it is attributed on p. 165 http://books.google.com/books?id=0qYXAQAAMAAJ&pg=PA165#v=onepage&q&f=false to Plato. It could possibly be a paraphrase of either or both of the following to comments in Kepler's 1618 book Harmonices Mundi (The Harmony of the World)': "Geometry is one and eternal shining in the mind of God" and "Since geometry is co-eternal with the divine mind before the birth of things, God himself served as his own model in creating the world".
μὴ εἶναι βασιλικὴν ἀτραπὸν ἐπί γεωμετρίαν, Non est regia [inquit Euclides] ad Geometriam via
Reply given when the ruler Ptolemy I Soter asked Euclid if there was a shorter road to learning geometry than through Euclid's Elements.The "Royal Road" was the road built across Anatolia and Persia by Darius I which allowed rapid communication and troop movement, but use of ἀτραπός (rather than ὁδός) conveys the connotation of "short cut".
The Greek is from Proclus (412–485 AD) in Commentary on the First Book of Euclid's Elements, the Latin translation is by Francesco Barozzi, 1560) the English translation follows Glenn R. Morrow (1970), p. 57 http://books.google.com/books?id=JZEHj2fEmqAC&q=royal#v=snippet&q=royal&f=false.
Original: (la) Non est regia ad Geometriam via.
— Euclid, livro Os Elementos
Καὶ τὸ ὅλον τοῦ μέρους μεῖζον
Elements, Book I, Common Notion 8 (5 in certain editions)
Cf. Aristotle, Metaphysics, Book Η 1045a 8–10: "… the totality is not, as it were, a mere heap, but the whole is something besides the parts … [πάντων γὰρ ὅσα πλείω μέρη ἔχει καὶ μὴ ἔστιν οἷον σωρὸς τὸ πᾶν]"
Original: (el) Καὶ τὸ ὅλον τοῦ μέρους μεῖζον [ἐστιν].
— Euclid, livro Os Elementos
Elements, Book 7, Definition 11 (12 in certain editions)
Original: (el) Πρῶτος ἀριθμός ἐστιν ὁ μονάδι μόνῃ μετρούμενος.