Definition:Set Intersection/Historical Note

Historical Note on Set Intersection
The concept of set intersection, or logical multiplication, was stated by in his initial conception of symbolic logic.

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

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

It was who took this symbol and used it for intersection, in his $1888$ work Calcolo geometrico secondo l'Ausdehnungslehre di H. Grassmann.

also created the large symbol $\bigcap$ for general intersection of more than two sets.

This appeared in his Formulario Mathematico (5th edtion, 1908).