# What Is a Ring?

Rings have long been worn as a sign of love and friendship. The Egyptian pharaohs, for example, used rings to symbolize eternity. The circle has no beginning or end, reflecting the shape of the moon and sun. The Egyptians believed the open space in the middle represented the “gateway to the unknown.” The ring was also the symbol of the ouroboros, a mythical creature that devours its tail and represents the everlasting cycle of things. Greek mythology also gives rings special symbolic meaning.

The mathematical definition of a ring is the set of all elements of a group, such as a group or a set. A ring is a set of elements that are invertible, such as a ring of integers. The term ring is used in books on algebraic geometry and commutative algebra.

In mathematics, rings are groups of elements that have a common center. When the center is a subring, it is referred to as a topological ring. Likewise, a ring of continuous functions is a subring of the ring of quadratic integers. Another type of ring is the ring of algebraic integers. Another ring of integers is a ring of n x n real square matrices with n>2.

The category C is associated with rings. A ring object is an object equipped with morphisms that define its category. An element in C is a ring if it is composed of elements x + y or x – m. A ring homomorphism is an inclusion map between two rings.

In addition to their astronomical importance, the rings of Saturn are beautiful and breathtaking to observe. A small telescope or handheld binoculars can make the rings visible. The first observations of Saturn’s rings came from Galileo in 1610, and since then, the rings are visible and accessible to the general public.

Rings were also common in Medieval Europe. Roman fede rings and portrait rings were popular. Later, fede rings were incorporated into gimmel rings that featured two or three interlocking bands. During the engagement period, couples wore an engagement band, and during the wedding ceremony, the groom would place it on the bride’s finger. The completed ring was a symbol of two right hands clasped together.

Diamond rings became popular during the seventeenth century. During this time, a man could give a woman a diamond as a pledge of love. These rings were often decorated with a third band and a gem clasped by two hands. The Elizabethan and Renaissance eras saw the rise of poetry rings. However, Puritans considered jewelry to be frivolous, and gave their wives thimbles instead. The marriage between two Italian socialites dates to the fourteenth century.