Definition:Set Union/Historical Note

Historical Note on Set Union
The concept of set union, or logical addition, was stated by in his initial conception of symbolic logic.

The symbol $\cup$, informally known as cup, was first used by in Die Ausdehnungslehre from $1844$.

However, he was using it as a general operation symbol, not specialized for set union.

It was who took this symbol and used it for union, in his $1888$ work.

also created the large symbol $\bigcup$ for general union of more than two sets.

This appeared in his of $1908$.