[Math] shorthand notation for adding an element to a set

elementary-set-theorynotation

I know that if you want to refer to the set $ A $ with the element $ x $ added, you can write $ A \cup \{x\} $. But is there a common shorthand for this?

Best Answer

There is no particular notation that I am aware of.

If you have a particular set in mind you can always write something such as:

We shall write $A(x)$ for the set $A\cup\{x\}$.

This is just a suggested notation, of course. Be careful that the readers won't confuse this with a function symbol (although it is a function symbol if you think about it). It might be easier to use $A_x$ in some cases (if font sizes are not bothering).

Whatever you do, though, write the explicit notation in your text.

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