In details

Origin of relation signs (=,)

Roberto Record, English mathematician, will always have his name pointed in the history of mathematics because he was the first to use the sign = (equal) to indicate equality.

In his first book, published in 1540, Record placed the symbol between two equal expressions; the = sign, consisting of two small parallel strokes, only appeared in 1557. Some authors comment that, in the manuscripts of the Middle Ages, the = sign appears as an abbreviation of the word est.

Guilherme Xulander, a German mathematician, indicated equality at the end of the sixteenth century by two small vertical parallel features; until then the word aequalis appeared at length, linking the two members of equality.

The> (greater than) and <(less than) signs are due to Thomaz Harriot, who greatly contributed his work to the development of algebraic analysis.