On Oct 29, 2012, at 6:12 AM, Thorsten Ottosen wrote:
On 28-10-2012 17:36, Jan Hudec wrote:
From what's written here, it's hard to know whether "cross product" is wrong or not, but given the number of samples cited, I'm inclined to believe it's probably right. What result other than the cross product do you think that means?
Any operation that is written with × is called cross product. However that symbol is used for different operations in different contexts. Best known are two meanings, the "vector product" used in physics and "cartesian product" used in set theory and relational algebra.
The kind of product we have here, set of tuples where first member is member of first operand and second member is member of second operand, is unambiguously called "cartesian product".
So I would probably call it "cartesian product", but "cross product" would not be incorrect.
+1 for Cartesian product. For me at least, "cross product" sounded very confusing.
My apologies -- I meant to say "Cartesian", not "cross". Database people do use the latter to mean the former, but it's ambiguous and clearly a violation of my desire to choose names carefully.