What is the meaning of yin-yang words? Is there any relevant theory?

Yin and Yang is a simple and broad philosophy.

The philosophy of Yin and Yang has three characteristics: opposition, mutualization and unity. In thinking, it is an inseparable metaphysical node between calculation (arithmetic) and divination (logic). Biological genes in nature and duality in artificial intelligence fully show the vitality of Yin and Yang.

Yin and Yang are the descriptions of the basic factors hidden behind the laws of nature and promoting the development and changes of the laws of nature in ancient China. They are the motive force for the gestation, development, maturity, decline and even extinction of all kinds of things, and are the core elements to lay the foundation of logical thinking of Chinese civilization. Generally speaking, according to Yi-ology, it describes the most basic elements of the universe and their functions, which is one of Fu's basic concepts.

There are four pairs of relations between Yin and Yang: the mutual body of Yin and Yang, the transformation of Yin and Yang, the opposition of Yin and Yang, and the same root of Yin and Yang.

Traditionally, Yin and Yang represent the most basic opposition of all things. It is the objective law of nature, the origin of the movement and change of all things, and the basic law of human understanding of things. The concept of Yin and Yang originated from the view of nature of ancient people in China. The ancients summed up the concept of yin and yang in a philosophical way by observing various opposing and related natural phenomena in nature, such as heaven and earth, sun and moon, day and night, cold and heat, men and women, up and down, etc.