The next talk in the Colloquium Series is:

Date: Wednesday, March 6, 2024
Speaker: Prof. Ximena Catepillán
Mathematics Department
Millersville University
Email: Ximena DOT Catepillan AT millersville DOT edu
Title: Maya Numbers and Calendrical Computations
Abstract: Mesoamerican calendars were many and complex. There have been a good number of studies done to decipher them. By the arrival of Hernan Cortes in 1519 in what is current day Mexico, there were 21 calendars in use while 4 of them were extinct. Using astronomical observations, the Maya developed an elaborate system of calendars, among them the Tzolkin Calendar, the Haab Calendar, the Round Calendar (a combination of the first two) and the Long Count. Which operations did the Maya use to perform their calendrical computations? While they used a vigesimal system to write the numbers, this system was never used in connection with days. No inscriptions use vigesimal numbers but rather quasi-vigesimal (chronological) numbers. In spoken numbers, a mix of decimal and vigesimal notation appears. Multiplication by 20 was the most common computation. They also needed to divide to do some of the calendar conversions. I'll illustrate calendrical computation within and among calendars and conversion examples in which division is needed. This technique is quite simple using just a pencil and paper.