RECEPCE PLATÓNOVA TIMAIA KOLEM ROKU 1000: FILOSOFICKÁ DŮLEŽITOST ROVNOSTR ANNÉHO TROJÚHELNÍKU PODLE GEOMETRIE A ARITMETIKY NA ZÁKLADĚ TEXTŮ GERBERTA Z AURILLACU A ADALBOLDA Z UTRECHTU.

The paper deals with the correspondence between Gerbert of Aurillac (from 999 Pope Sylvester II, † 1003) and Adalbold (from 1010 Bishop of Utrecht, † 1026/27). Both scholars wrote, in addition to other works, several short texts focused on mathematical problems, including letters addressed to each other. The paper presents, mainly with respect to Gerbert’s letter to Adalbold regarding the area of the equilateral triangle according to geometric and arithmetic rules, the broader context and aims of these mathematical disciplines in the Early Middle Ages. The emphasis is especially on inspiration from ancient and older Early Medieval sources (e.g. Plato, Calcidius, Boethius or Victorius of Aquitaine, the so-called Pseudo-Boethius’ Geometria I and Geometria II), but also other contemporary sources (Abbo of Fleury, Geometria incerti auctoris, etc.) and other texts by Gerbert (primarily Geometria attributed to him) and Adalbold (especially The Commentary to Boethius’ Consolation, III,9). The main goal of the paper is to demonstrate the extremely close relationships between the mathematical and philosophical interpretation of the created world, in accordance with Plato’s legacy. [ABSTRACT FROM AUTHOR]