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Mathematische Wissenschaften

(2,233 words)

Author(s): Menso Folkerts
A. Begriff und antike Grundlagen Unter M. W. werden hier Arithmetik, Geometrie und Algebra verstanden, nicht aber Gebiete der angewandten Mathematik wie Geodäsie und Kartographie. In der Antike umfassten die M. W. das Quadrivium, d. h. Arithmetik, Geometrie, Astronomie und Musiktheorie (Musik). Die Arithmetik behandelte die ganzen Zahlen und deren Beziehungen zueinander, nicht aber das praktische Rechnen. Zentral waren die Teilbarkeit von Zahlen (Primzahlen, vollkommene Zahlen) und die Proportionenle…
Date: 2017-04-01

Sporos

(134 words)

Author(s): Folkerts, Menso
[English version] (Σπόρος) oder Poros (Πόρος). Es ist unklar, ob beide Personen, die um 200 n. Chr. lebten, identisch sind (s. [5]). S. bzw. P. verfaßte eine (verlorene) Kompilation Κηρία ( Kēría) mit Auszügen über die Kreisquadratur und Würfelverdopplung [4. 226]. Er kritisierte Archimedes' [1] Approximation der Zahl Pi (so [1. 258,22]), gab einen eigenen Lösungsversuch des Problems der Würfelverdopplung [1. 76-78; 4. 266-268] und lehnte die Quadratrix des Hippias [5] von Elis ab [2. 252-254; 4. 229-230]. In den Aratscholie…

Theudios

(176 words)

Author(s): Folkerts, Menso
[English version] (Θεύδιος). Mathematiker und Philosoph aus Magnesia, wohl 4. Jh. v. Chr. Die einzigen Informationen über ihn stammen aus dem Mathematikerkatalog in Proklos' [2] Euklid-Komm. [1. 67, Z. 12-20]. Dort erscheint er nach Eudoxos [1] und vor Philippos von Medma, der ein Schüler Platons [1] war; Th. war also wohl ein Zeitgenosse des Aristoteles [6]. Nach Proklos betrieb Th. mit Menaichmos [3] und Deinostratos gemeinsame Forsch. an der Akademie ( Akadḗmeia ), brachte die “Elemente” in ein geordnetes System und gab vielen definitionsar…

Würfelverdopplung

(1,004 words)

Author(s): Folkerts, Menso
(κύβου διπλασιασμός/ kýbu diplasiasmós nach Eratosthenes, in [1. 88,16]). [English version] I. Allgemein Die W. gehört - neben der Winkeldreiteilung (Winkel- und Kreisteilung) und der Kreisquadratur - zu den drei klass. Problemen der griech. Mathematik. Gefordert ist: Zu einem gegebenen Würfel mit der Seitenlänge a (also dem Volumen a 3) durch ein geom. Verfahren die Seite x eines anderen Würfels zu finden, dessen Volumen doppelt so groß wie der gegebene Würfel ist. Gesucht ist also die Größe x, für die gilt: x 3 = 2 a 3 (d. h.: x = a 32). Die Aufgabe läuft demnach auf eine Kubikwur…

Kreisquadratur

(1,132 words)

Author(s): Folkerts, Menso
(ὁ τοῦ κύκλου τετραγωνισμός/ ho tu kýklu tetragōnismós, lat. quadratura circuli). [English version] I. Wesen des Problems Die K. gehört zu den drei “klass. Problemen” der Mathematik (die beiden anderen sind die Winkeldreiteilung, vgl. Winkel- und Kreisteilung, und die Würfelverdopplung). Die Aufgabe lautet: Zu einem gegebenen Kreis (= Kr.) mit dem Radius r ist durch ein geom. Verfahren die Seite x eines Quadrats zu finden, das die gleiche Fläche wie der Kr. aufweist. Es wird also die Größe x gesucht, für die gilt: x 2 = π r 2. Die Lösung der K. ist demnach eng mit dem Wesen der Z…

Thymaridas

(153 words)

Author(s): Folkerts, Menso
[English version] (Θυμαρίδας). Mathematiker von Paros, der von Iamblichos (v. P. 104) zu den frühen Pythagoreern (Pythagoreische Schule) gerechnet wird. Er definierte die “Einheit” (μονάς/ monás; d. h. die Eins, die alle natürlichen Zahlen erzeugt) als περαίνουσα ποσότης ( peraínusa posótēs, “begrenzende Quantität”; Iambl. in Nicomachi arithmeticam introductionem 11,2-5) und nannte die Primzahl εὐθυγραμμικός ( euthygrammikós, “geradlinig”; ebd. 27,4), weil sie sich nur eindimensional darstellen läßt. Mit dem Namen “Blume des Th.” (Θυμαρίδειον ἐπάνθημα, Thymarídeion e…

Mathematik

(2,968 words)

Author(s): Folkerts, Menso
Folkerts, Menso [English version] A. Einleitung (RWG) Ausgehend von den mathematischen Leistungen der Ägypter und Babylonier hatten die Griechen die M. zu einem deduktiven System umgebaut, das auf einer Theorie des Beweisens beruhte. Anders als für ihre Vorgänger, war für die Griechen die M. eine um ihrer selbst willen betriebene Wiss., die auch ihre Grundlagen untersuchte; praktische Erwägungen und unmittelbar numerische Probleme traten in den Hintergrund. Die Hauptleistungen der Griechen betrafen die…

Serenos

(178 words)

Author(s): Folkerts, Menso
[English version] (Σέρηνος). Mathematiker aus Äg. (Antinoupolis), lebte wahrscheinlich im 4. Jh. n. Chr. S. verfaßte zwei (vollständig erh.) Schriften über Kegelschnitte: In Περὶ κυλίνδρου τομῆς ( Perí kylíndru tomḗs, ‘Über den Schnitt eines Zylinders; Ed. [1. 2-117], Übers. [2; 4. 1-64]) beweist er Sätze über die Gleichheit von Zylinder- und Kegelschnitten und über die Projektion des Zylinders in die Ebene. In Περὶ κώνου τομῆς ( Perí kṓnu tomḗs, ‘Über den Schnitt eines Kegels; Ed. [1. 120-303], Übers. [3; 4. 65-167]) werden Sätze und Aufgaben über Schnitte…

Landvermessung

(841 words)

Author(s): Folkerts, Menso
[English version] Die Schriften der röm. Feldmesser (Agrimensoren) behandeln deren verschiedene Wirkungsbereiche: Vermessung von Gebieten; Limitation, d. h. Einteilung durch sich rechtwinklig schneidende Grenzlinien; Anlage von Katastern und Flurkarten; Tätigkeit als Richter oder Sachverständige im Bodenrecht, insbes. bei Grenzstreitigkeiten; Mitwirkung bei rel. Akten; Längen- und Flächenmaße, Gewichte und die Inhaltsbestimmung von Flächen und Körpern. Mit mathematischen Fragen beschäftigen sich v. a. Balbus' Schrift Expositio et ratio omnium formarum (ca. 10…

Winkel- und Kreisteilung

(804 words)

Author(s): Folkerts, Menso
[English version] I. Alter Orient s. Mathematik I. Folkerts, Menso II. Klassische Antike [English version] A. Kreisteilung Die Kreisteilung, d. h. die Teilung des Kreisumfangs in eine beliebige Anzahl gleichlanger Bögen, hängt unmittelbar mit den regelmäßigen Vielecken (Polygonen) zusammen: Wenn in einen Kreis ein regelmäßiges n-Eck einbeschrieben wird, so wird der Kreisumfang in n Abschnitte geteilt, und der zur Seite des n-Ecks gehörende Mittelpunktswinkel hat den Wert 360°/ n . Schon die Pythagoreer (Pythagoras [2]) interessierten sich für die regelmäßigen …

Division of angles and circles

(923 words)

Author(s): Folkerts, Menso (Munich)
[German version] I. Ancient Orient see  Mathematics I Folkerts, Menso (Munich) II. Classical Antiquity [German version] A. Division of circles The division of circles, i.e. the division of the circumference of a circle into any number of arcs of equal length, is directly correlated to the regular polygons: if a regular n-gon is inscribed in a circle, the circumference of the circle is divided into n sections and the angle at the centre belonging to the side of the n-gon has the value 360°/ n . The Pythagoreans ( Pythagoras [2]) were already interested in the regular polygons a…

Mathematical sciences

(2,201 words)

Author(s): Folkerts, Menso (München)
A. Concept and ancient originsThe M. are considered to be arithmetic, geometry and algebra, but not fields of applied mathematics like geodesy or cartography. In Antiquity, they comprised the quadrivium, i.e. arithmetic, geometry, astronomy and music theory. Arithmetic concerned the integers and their relationships,  but not practical calculation. At its heart was the divisibility of integers (prime numbers, perfect numbers) and the theory of proportion. The Greeks knew that there were magnitudes that lacked a common meas…
Date: 2016-11-24

Mesolabium

(99 words)

Author(s): Folkerts, Menso (Munich)
[German version] (μεσολάβιον; mesolábion). A mechanical device invented by Eratosthenes [2] to establish graphically the two geometric means x and y between two given lines a and b (as in the relationship a: x = x: y = y: b). The mesolabium enabled the mechanical solution of the problem of the duplication of the cube (‘Delian problem’): if b = 2 a, then x is the desired solution of the equation for the duplication of the cube ( x3 = 2a3 ). Hippocrates [5] of Chios Folkerts, Menso (Munich) Bibliography mes T. L. Heath, A History of Greek Mathematics, Vol. 2, 1921, 258-260.

Rhombus

(103 words)

Author(s): Folkerts, Menso (Munich)
(ῥόμβος/ rhómbos). [German version] [1] Geometric shape In the plane, a rectangle with four sides of equal length but with unequal angles ( i.e., with two acute and two obtuse angles; Euc. 1, Def. 22; Censorinus, DN 83,14 Jahn). In three dimensions, a rhombus is the solid of revolution consisting of two cones with the same base (Archim. De sphaera et cylindro 1, def. 6). Folkerts, Menso (Munich) Bibliography 1 T. L. Heath, The Thirteen Books of Euclid's Elements, vol. 1, 21925, 189 2 A. Hug, s.v. Ῥόμβος ( rhombus), RE 1 A, 1069. [German version] [2] See Top see Top [German version] [3] See Rho…

Neusis

(124 words)

Author(s): Folkerts, Menso (Munich)
[German version] (νεῦσις/ neûsis, ‘inclination’, in the mathematical sense: ‘verging’) is a geometric operation that cannot be performed with a compass and ruler alone. It allows problems  that lead to cubic and other higher equations (for example, cube duplication, angle trisection, squaring the circle) to be solved geometrically. A neûsis construction is necessary when a straight line through a given point is supposed to intersect two given lines so that the distance between the points of intersection is equal to a certain distance. Nicomede…

Quadrature of the circle

(1,369 words)

Author(s): Folkerts, Menso (Munich)
(ὁ τοῦ κύκλου τετραγωνισμός/ ho toû kýklou tetragōnismós, Latin quadratura circuli). [German version] I. The nature of the problem The quadrature of the circle is one of the three 'classic problems' (the other two being the trisection of an angle, cf. division of angles and circles, and the duplication of the cube) of ancient Greek mathematics. The problem is to find the side x of a square such that its area is equal to the area of a circle with radius r using a geometric procedure; that is,  to determine the value of the variable x in the equation x 2 = π r 2. Accordingly, the solution to the q…

Theudius

(210 words)

Author(s): Folkerts, Menso (Munich)
[German version] (Θεύδιος; Theúdios). Mathematician and philosopher from Magnesia, probably 4th century BC. The only information about him comes from the catalogue of mathematicians in Proclus's [2] commentary on Euclid [1. 67, Z. 12-20]. T. is mentioned there after Eudoxus [1] and before Philippus of Medma, who was a pupil of Plato [1]; Therefore, T. was probably a contemporary of Aristotle [6]. According to Proclus, T., Menaechmus [3] and Deinostratus conducted research together at the Academy ( Akadḗmeia ), improved the arrangement of the 'Elements', and put many limited pr…

Eutocius

(168 words)

Author(s): Folkerts, Menso (Munich)
[German version] (Eυτόκιος; Eutókios) The mathematician E. of Ascalon was presumably born around AD 480; the widespread assumption that he was a pupil of the architect  Isidorus of Miletus is hardly plausible [1. 488]. He wrote commentaries on three works of  Archimedes [1] ( Perì sphaíras kaì kylíndrou, Περὶ σφαίρας καὶ κυλίνδρου, kýklou métrēsis, κύκλου μέτρησις, Perì epipédōn isorrhopiôn, Περὶ ἐπιπέδων ἰσορροπιῶν, text editions [3. 1-319]) as well as on the first four books of Apollonius' Kōniká (Κωνικά) [13] (dedicated to  Anthemius [3], text edition [4. 168-361]…

Gnomon

(272 words)

Author(s): Folkerts, Menso (Munich)
[German version] [1] see Groma see  Groma (surveying) Folkerts, Menso (Munich) [German version] [2] see Clocks see  Clocks (time measurement) Folkerts, Menso (Munich) [German version] [3] Arithmetic technical term Arithmetic technical term from Greek numerical theory. The term was adopted from geometry, where the gnomon describes the shape of an angle bar that remains when a smaller square is removed from a larger square. The Pythagoreans represented arithmetic series with geometrically arranged dots (pebbles) in the form of figures, so t…

Mechanical method

(255 words)

Author(s): Folkerts, Menso (Munich)
[German version] The ‘Method (Ἔφοδος; Éphodos) of Archimedes [1] is our source for his mechanical method from which he derived geometric formulas. To compare the surfaces of two figures, he disassembled each into an infinite number of parallel lines and balanced them on a scale. On one side of the scale, one surface is hung up at one point, i.e., as a whole. On the other side, the surface is hung up along the entire arm, i.e., each layer remains where it is and acts with a different leverage. When ea…

Axi­om

(143 words)

Author(s): Folkerts, Menso (Munich)
[German version] In the same way as postulates, axioms were presumably introduced in conflict with Eleatic philosophy in order to enable the acceptance of the existence of the manifold [1. 322-325; 2; 3]. According to Aristotle, axioms are central to every branch of knowledge, particularly the law of contradiction and the principle of the excluded middle (Metaph. Γ 3,1005a19-b27); for the organization of the fundamental principles of a branch of knowledge wherein proof is sought see Aristot. An. p…

Mathematics

(3,425 words)

Author(s): Folkerts, Menso (Munich)
Folkerts, Menso (Munich) [German version] A. Introduction (CT) Taking their point of departure from the mathematical accomplishments of the Egyptians and Babylonians, the Greeks remodelled mathematics into a deductive system based on a theory of proof. For the Greeks, unlike for their predecessors, mathematics was a science practiced for its own sake, which also investigated its own foundations; thus, practical considerations and directly numerical problems faded into the background. The main accomplish…

Deinostratus

(385 words)

Author(s): Folkerts, Menso (Munich)
[German version] (Δεινόστρατος; Deinóstratos) D. is mentioned in Eudemus' list of mathematicians as the brother of Menachmus, who was a pupil of Eudoxus (Procl. in primum Euclidis elementorum librum comm., p. 67,11 Friedlein). He therefore lived in the middle of the 4th cent. BC  Pappus of Alexandria reports (4,30, p. 250,33-252,3 Hultsch) that to square the circle D. used a curve that was accordingly called the quadratrix (τετραγωνίζουσα). This curve, said to have already been used by Hippias of Elis for the trisection…

Thymaridas

(162 words)

Author(s): Folkerts, Menso (Munich)
[German version] (Θυμαρίδας; Thymarídas). Mathematician from Paros; according to Iamblichus (v. P. 104), T. was an early Pythagorean (Pythagorean School). He defined 'unity' (μονάς/ monás; i.e. the One that generates all the natural numbers) as περαίνουσα ποσότης ( peraínousa posótēs, 'limiting quantity'; Iambl. in Nicomachi arithmeticam introductionem 11,2-5) and called prime numbers εὐθυγραμμικός ( euthygrammikós, 'rectilinear'; ibid.  27,4), because they can only be set out in one dimension. The name 'Flower of T.' (Θυμαρίδειον ἐπάνθημα, Thymarídeion epánthēma) is gi…

Hypsicles

(603 words)

Author(s): Folkerts, Menso (Munich)
[German version] (Ὑψικλῆς; Hypsiklês). Hellenistic mathematician and astronomer. From the introduction to book 14 of Euclid's ‘Elements’ written by him, it follows that H. lived in Alexandria around 175 BC. It is attested by MSS that he composed what later was added as book 14 to the ‘Elements’ of  Euclides [3] (ed. [1]). Like bk. 13 it deals with the inscribing of regular bodies into a sphere and was thought of as an explanation to a lost work of  Apollonius [13] about dodecahedra and icosahedra. H. shows that the planes th…

Pappus of Alexandria

(727 words)

Author(s): Folkerts, Menso (Munich)
(Πάππος Ἀλεξανδρεύς; Páppos Alexandreús). [German version] I. Life Eminent Greek mathematician. Based on his calculation of a partial solar eclipse for the year AD 320, it is assumed that P. lived in the first half of the 4th cent. (on this and on erroneous dating in the Suda see [2. 2-4]). Folkerts, Menso (Munich) [German version] II. Works The most important surviving work is the Συναγωγή/ Synagōgḗ, customarily cited as the Collectio (ed. [1], French translation [3], edition and English translation of book 7 [2]). Of the 8 books, the first is wholly lost, the se…

Duplication of the Cube

(1,109 words)

Author(s): Folkerts, Menso (Munich)
(κύβου διπλασιασμός/ kýbou diplasiasmós according to Eratosthenes, in [1. 88,16]). [German version] I. General The duplication of the cube ─ besides the  division of angles and circles and the  squaring of the circle ─ belongs to the three classic problems in Greek  mathematics. The challenge is such: to find ─ through the use of geometry ─ for a given cube with a side-length of a (and thus the volume of a 3) the side x of another cube whose volume is twice as big as that of the given cube. The problem is therefore to find the value of x, to which applies: x 3 = 2 a 3 (that is: x = a 32). The problem thus…

Land surveying

(895 words)

Author(s): Folkerts, Menso (Munich)
[English version] The writings of the Roman surveyors ( agrimensores) deal with their various areas of activity: measurement of areas; limitation, i.e. division by orthogonal boundaries; creation of land registers and general parceling maps; functioning as a judges or experts in land law, particularly in boundary disputes; collaboration in religious ceremonies; units of length and area, weights and determining area and volume. Mathematical questions are dealt with most notably by Balbus' work Expositio et ratio omnium formarum (ca . AD 100), the anonymous Liber podismi and a wo…

Neusis

(106 words)

Author(s): Folkerts, Menso (München)
[English version] (νεῦσις, eigentlich: “Neigung”, im mathematischen Sinne: “Einschiebung”) ist eine geom. Operation, die nicht allein mit Zirkel und Lineal durchführbar ist. Mit ihrer Hilfe können Probleme, die auf kubische und andere höhere Gleichungen führen (z.B. Würfelverdoppelung, Winkeldreiteilung, Kreisquadratur) geom. gelöst werden. Eine N. ist notwendig, wenn eine durch einen gegebenen Punkt laufende Gerade zwei gegebene Linien so schneiden soll, daß der Abstand der Schnittpunkte einer ge…

Mechanische Methode

(233 words)

Author(s): Folkerts, Menso (München)
[English version] Aus der ‘Methodenlehre (Ἔφοδος) des Archimedes [1] kennen wir seine m.M., mit deren Hilfe er geometrische Formeln herleitet. Um Flächen von zwei Figuren zu vergleichen, zerlegt er jede von ihnen in unendlich viele parallele Strecken und balanciert sie auf einer Waage. An einen Waagebalken wird die eine Fläche in einem Punkt, also als Ganzes, aufgehängt. Auf der anderen Seite der Waage wirkt die Fläche auf den ganzen Balken, d.h. jede Schicht bleibt, wo sie ist, und wirkt mit eine…

Mesolabion

(91 words)

Author(s): Folkerts, Menso (München)
[English version] (μεσολάβιον, lat. mesolabium). Eine von Eratosthenes [2] erfundene mechanische Vorrichtung, um zwischen zwei gegebenen Strecken a und b die beiden mittleren Proportionalen x und y (gemäß der Beziehung a: x = x: y = y: b) durch Verschieben zu bestimmen. Das M. ermöglicht es, das Problem der Würfelverdopplung (“Delisches Problem”) mechanisch zu lösen: Ist b = 2 a, so ist x die gesuchte Lösung der Gleichung für die Würfelverdopplung ( x3 = 2a3 ). Hippokrates [5] von Chios Folkerts, Menso (München) Bibliography T.L. Heath, A History of Greek Mathematics, Bd. 2, 192…

Hypsikles

(562 words)

Author(s): Folkerts, Menso (München)
[English version] (Ὑψικλῆς). Hell. Mathematiker und Astronom. Aus der Einl. zu dem von ihm stammenden B. 14 von Euklids ‘Elementen folgt, daß H. um 175 v.Chr. in Alexandreia lebte. Durch Hss. wird bezeugt, daß er die Schrift verfaßt hat, die spä…

Rhombus

(96 words)

Author(s): Folkerts, Menso (München)
(ῥόμβος). [English version] [1] geometrische Figur In der Ebene ein Viereck mit gleich langen Seiten, aber ungleichen (d. h. zwei spitzen und zwei stumpfen) Winkeln (Eukl. elem. 1, Def. 22; Cens. 83,14 Jahn). Im Raum ist rh. der Rotationskörper, der aus zwei Kegeln mit gleicher Grundfläche besteht (Archim. de sphaera et cylindro 1, Def. 6). Folkerts, Menso (Münc…

Axiome

(131 words)

Author(s): Folkerts, Menso (München)
[English version] Die A. sind, ähnlich wie die Postulate, vermutlich in Auseinandersetzung mit der eleatischen Philos. eingeführt worden, um die Existenz der Vielheit annehmen zu können [1. 322-325; 2; 3]. Nach Aristoteles sind die A. zentral für jede Wiss., insbes. der Satz vom Widerspruch und ausgeschlossenen Dritten (metaph. Γ 3,1005a19-b27Aristot. metaph. Γ 3,1005a19-b27); zur Einteilung der Grundlagen für eine beweisende Wiss. s. Aristot. an. post. 1,2,72a14-24. Bei Eukleides w…

Gnomon

(257 words)

Author(s): Folkerts, Menso (München)
[English version] [1] s. Groma s. Groma (Landvermessung) Folkerts, Menso (München) [English version] [2] s. Uhr s. Uhr (Zeitmessung) Folkerts, Menso (München) [English version] [3] Arithmetischer t.t. Arithmetischer t.t. aus der Zahlentheorie der Griechen. Der Begriff wurde aus der Geometrie übernommen, wo der G. die Figur eines Winkelhakens bezeichnete, der übrig blieb, wenn man aus einem größeren Quadrat ein kleineres ausschnitt. Die Pythagoreer stellten arithmetische Folgen durch geometrisch angeordnete Punkte (Steinch…

Heron

(1,049 words)

Author(s): Folkerts, Menso (München)
(Ἥρων). [English version] A. Leben H. von Alexandreia, Mathematiker und Ingenieur. Über sein Leben sind keine Einzelheiten…

Pappos von Alexandreia

(672 words)

Author(s): Folkerts, Menso (München)
(Πάππος Ἀλεξανδρεύς). [English version] I. Leben Bedeutender griech. Mathematiker. Da er eine partielle Sonnenfinsternis für das Jahr 320 n.Chr. berechnet hat, fällt seine Lebenszeit in die erste H. des 4. Jh. (hierzu und zur fehlerhaften Datier. in der Suda s. [2. 2-4]). …

Eutokios

(158 words)

Author(s): Folkerts, Menso (München)
[English version] Der Mathematiker E. von Askalon wurde vermutlich um 480 n.Chr. geb.; die verbreitete Annahme, er sei Schüler des Architekten Isidoros von Milet gewesen, dürfte nicht zutreffen [1. 488]. Er verfaßte Komm. zu drei Schriften des Archimedes [1] (

Deinostratos

(337 words)

Author(s): Folkerts, Menso (München)
[English version] Im Mathematikerverzeichnis des Eudemos wird D. als Bruder des Menaichmos erwähnt, der ein Schüler von Eudoxos war (Prokl. in primum Euclidis elementorum librum comm., p. 67,11 Friedlein). Er lebte demnach Mitte des 4. Jh.v.Chr. Pappos von Alexandreia berichtet (4,30, p. 250,33-252,3 Hultsch), D. habe für die Quadratur des Kreises eine Kurve gebraucht, die deshalb Quadratrix (τετραγωνίζουσα) gen. wurde. Bei dieser Kurve, die schon Hippias von Elis für die Winkeldreiteilung benutzt haben soll, gl…

Geminus

(723 words)

Author(s): Folkerts, Menso (Munich) | Albiani, Maria Grazia (Bologna)
(Γέμινος; Géminos) [I]. [German version] [1] Astronomer and mathematician Astronomer and mathematician from the school of Posidonius. Almost nothing is known about his life. The height of his creativity was around 70 BC. It is generally accepted that he lived in Rhodes. The only fully extant treatise by G. is the ‘Introduction to Astronomy’ (Εἰσαγωγὴ εἰς τὰ φαινόμενα). It is in the tradition of  Eudoxus and  Aratus [4]. Similarly to the later writing by  Cleomedes, it is an elementary textbook on astrono…

Sporus

(279 words)

Author(s): Folkerts, Menso (Munich) | Eck, Werner (Cologne)
[German version] [1] Mathematician, c. AD 200 (Σπόρος; Spóros) or Porus (Πόρος; Póros). It is unclear whether the two individuals of this name living around AD 200 are in fact the same person (v. [5]). S. or Porus wrote a (lost) compilation, Κηρία ( Keria), with extracts on the quadrature of the circle and the duplication of the cube [4. 226]. He criticized Archimedes' [1] approximation of the number pi (thus [1. 258,22]), provided his own solution to the problem of the duplication of the cube [1. 76-78; 4. 266-268] and rejected the Quadratrix of Hippias [5] of Elis [2. 252-254; 4. 229-230]. He appears in the Aratus scholia [3] as the editor and critical annotator of Aratus' [4] …

Mathematics

(6,466 words)

Author(s): Høyrup, Jens (Roskilde) | Folkerts, Menso (Munich)
Almost all we know about the mathematics of the pre-Greek cultures of the Ancient Near East, essentially Mesopotamian and Egyptian mathematics, originates from written sources. These are mainly from the scribal traditions, even though some sources give a glimpse of the mathematics of ‘lay’ practitioners. When scribes were concerned with the properties of mathematical objects, the purpose was always to calculate something. That is always true in professional practice, but it also holds for school texts, even when these deal with situations …

Aristaeus

(716 words)

Author(s): Schachter, Albert (Montreal) | Folkerts, Menso (Munich)
(Αρισταιο̃ς; Aristaîos). …

Hermotimus

(132 words)

Author(s): Wiesehöfer, Josef (Kiel) | Folkerts, Menso (Munich)
[German version] [1] Prisoner of war from Pedasa Prisoner of war from Pedasa, who, according to Hdt. 8,104f., as a eunuch, had become one of the closest confidants of  Xerxes I and is said to have taken his revenge on t…

Leodamas

(261 words)

Author(s): Engels, Johannes (Cologne) | Folkerts, Menso (Munich)
(Λεωδάμας; Leōdámas). [German version] [1] Athenian orator, c. 400 BC The Athenian L. of Acharnae, a skilful orator (Aristot. Rh. 2,23,25 1400a 31-35), was rejected at his

Theaetetus

(1,081 words)

Author(s): Folkerts, Menso (Munich) | Albiani, Maria Grazia (Bologna)
(Θεαίτητος; Theaítētos). [German version] [1] T. of Athens, mathematician, c. 400 BC Mathematician, a native of Athens, pupil of Theodorus [2] of Cyrene and later a member of Plato's Academy ( Akadḗmeia ). In Plato's [1] dialogue named after him, T. appears (together with the aged Theodorus [2]) as about fifteen years old in 399 BC; he was therefore born c. 414. Plato describes him as gentle, courageous and quick to apprehend. After he had been wounded in the battle of Corinth, T. contracted dysentery and died in 369. T. contributed substantially to the theory of irrational quantities. He studied and classified (linearly) incommensurable magnitudes whose squares are commensurable. This classification of irrational quantities can be found in Book 10 of Euclid's (Euclides [3]) Elements, which suggests that this book could hark back to T. ([10. 271-282]; sceptical: [1. 303]). Plato (Tht. 147d-148b) describes how T. distinguished between line segments that when squared produce a square number, and those that do not; T. calls the latter δυνάμει ( dynámei = potentially, i.e. in the second power) commensurable with the forme…

Hero

(1,389 words)

Author(s): Folkerts, Menso (Munich) | Waldner, Katharina (Berlin)
[German version] [1] Of Alexandria, mathematician and engineer, 1st cent. AD (Ἥρων; Hḗrōn). [German version] A. Life H. of Alexandria, mathematician and engineer. No details of his life are known. He lived after  Archimedes [1], whom he quotes, and before  Pappus, who quotes him. In the Dioptra, ch. 35, H. describes a method for determining the time difference between Rome and Alexandria by observing the same eclipse of the moon at both locations. It is quite likely that this eclipse occurred in AD 62 and that H. probably observed it himself in Alexandria [10. 21-24]. Folkerts, Menso (Mu…

Autolycus

(734 words)

Author(s): Graf, Fritz (Columbus, OH) | Folkerts, Menso (Munich)
(Αὐτόλυκος; Autólykos). [German version] [1] Son of Hermes and Chione Son of Hermes and Chione (or Philonis, who also bore the singer  Philammon to Apollo, Hes. fr. 64,14). He was included in various mythical family circles, as the father of  Odysseus' mother Anticlea (Hom. Od. 11,85), of  Jason's mother Polymede (Apollod. 1,107) and of Aesimus, the father of  Sinon. He gives the newborn Odysseus his name, and it is whilst hunting with his sons on Mount Parnassus that Odysseus receives the wound in his th…

Carpus

(196 words)

Author(s): Frey, Alexandra (Basle) | Folkerts, Menso (Munich)
(Κάρπος; Kárpos). [German version] [1] Son of Zephyrus and a certain Hore Handsome youth, son of Zephyrus and of a certain Hore ( Horae). He organizes a swimming race with  Calamus, his best friend, but drowns in the event. In mourning, his friend kills himself and is turned into reeds. C. is turned into a crop of the field (Nonnus, Dion. 11,385-481). Frey, Alexandra (Basle) [German version] [2] C. of Antioch Mathematician A mathematician, who lived presumably in the 1st or 2nd cent. AD. Information on him is given in four fragments by Pappus (8,3), Proclus (in Euc…

Archimedes

(2,119 words)

Author(s): Folkerts, Menso (Munich) | Degani, Enzo (Bologna)
[1] of Syracuse C. 287-232 BC [German version] A. Life A. was born in 287 BC in Syracuse, son of the astronomer Phidias. He was friends with King Hieron II, and later with his son Gelon. A. probably spent some time in Alexandria; he later sent on his writings to the mathematicians (Conon, Dositheus, Eratosthenes) who were working there. In Syracuse, A. studied problems of mathematical and physical theory, but also their practical applications; the machines and physical apparatus which he built (e.g. the s…
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