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).