The symbol ofinfinite ∞ We know him well: a “eight turned upside down”, a figure that actually makes the mathematical concept of unlimited perfectly, because it can be traveled to infinity given its closed shape. But .. it’s like that for zero! And therefore, where it comes from This symbol, what does it mean and why does this form have? It was introduced for the first time in 1659 by the English mathematician John Wallis.
Let’s see why in this article and we also see i controls to be used to express it on ours keyboard computer.
Where does the symbol of infinity ∞ come from
The symbol of infinity ∞ – also said lemniscata From the name of the algebraic curve that describes it – it looks like an eight turned upside down, but its origin is very different. The form ∞ expresses very well the concept of infinity, which indicates an unlimitedly large size that can grow unlimitedly, that is – in fact – without end.
The first mathematician to use this symbol to express the concept of infinity was the mathematical English John Wallis which, in 1659 within his work De sectionibus conicis On the conical sections, he wrote as follows:
Esto enim ∞ note infinite numbers
That is, literally “this symbol ∞ denotes infinite numbers”.
It took some time before reaching the systematic use of this symbol, which took hold only in 1800.
But why did Wallis choose this eight inverted?
The meaning of the infinity symbol
The hypothesis on why Wallis chose ∞ as a symbol for infinity is not univocal, but there are some more solid theses than others.
The most recognized is that ∞ comes from a variant of Roman number used for the number 1000, that was written as M but also like Ciɔ or, more simply Cɔ Which, as you can see, has a great similarity with the symbol ∞. The Cɔ Symbol In addition to expressing quantity 1000, it was used for understand “many”from which the comparison with infinity. According to the historian of mathematics Georges Ifrah, both the M and Ciɔ and consequently ∞, derive from deformations of the Greek letter Phi φ. The thesis of the Cɔ symbol as the father of ∞ is among other things supported by aengraving of 1588 found on a wall of Viterbo where it is seen written in Roman numerals ∞DLXXXVIII to indicate the year 1588, So where ∞ is replacing the letter m of 1000.
Other interpretations see the origin of ∞ la Greek letter omega Ω whose form recalls that of the infinity and which occupies the last position in the Greek alphabet, hence the idea of unlimited.
According to some, the form could also derive fromUroboro – Ouroboros – a symbol that depicts a snake that bites the tail and that was used as a sign of eternity and of the cosmos. According to others, however, it could be a “simplification” of theAnalemma, that is, the figure that is formed in the sky if we photograph the Sun during the year always from the same point and at the same time.
How to make the symbol of the infinity on the keyboard
As with many other mathematical symbols, there are shortcut (shortcuts) to make them directly in a text with our computer. As usual, Mac and Windows use different commands:
- For Windows the commands are Alt + 236 or Alt + 8734 If the computer is equipped with a numeric keypad
- Always for Windows, they are Alt + fn + 236 or Alt + fn + 8734 If the computer has only the Alfanumerica unique keyboard
- For Mac, the single command is Option + G
