This is the somewhat forgotten history of mathematics that developed in the East when the demise of ancient Greece slowed the progress of that science in the West.

The first steps of the mathematical journey of man were given by the ancient cultures of Egypt, Mesopotamia and Greece, cultures that created the base language of number and calculation.

But when ancient Greece fell into decay, mathematical progress stopped … in the West. In the east it rose to new heights.

Much of this mathematical heritage often does not get the credit it deserves.

Let’s talk about one particular Chinese mathematical heritage, as the BBC reported.

A sexual mathematical problem

One of the tasks of the imperial mathematical advisors was to create a system with which the emperor could lie down with as many women in his harem as possible.

The legendary yellow emperor ruled, according to the tradition of 2698 to 2598 a. C. He is credited with the introduction of wooden houses, cars, boats, bow and arrows, writing and the use of conceived money. His wife is credited with the discovery of silk culture (silk production).

The legend says that in 15 nights the emperor had to have relations with 121 women:

The Empress,

3 senior associates or ‘ladies’,

9 women or ‘invited ladies’,

27 concubines or ‘hereditary ladies’ and

81 slaves or ‘visiting ladies’.

The mathematical consultants found the solution on the basis of a given idea geometric progression.

They noticed that it was a series of numbers in which you go from one digit to another each time by multiplying the same number each time, in this case 3.

Each group of women is three times larger than the previous group, so they could organize a rotation that guaranteed it, in space of 15 overnight stays the emperor will sleep with all the women of the harem.

The first night was reserved for the Empress. The next, for the 3 superior partners. The nine women came later, and then the 27 concubines, in groups of 9 each night.

Eventually, during a period of 9 nights, the 81 slaves passed their beds in groups of 9.

It cannot be denied san emperor is necessary of very resistance.

The rotation also ensured that the emperor slept with the taller ladies on the nights closest to the full moon, when his yin– their female strength – was at its highest level and able to match its own yangor male strength.

The goal was clear and imperative: to seek the best possible imperial succession.