Table B-1.Mathematical Symbols Related to Sets and Functions

Symbol	Description	Examples
:=	Is defined as	P1 := x > y
∈, ∉	Is (not) an element of	x ∈ A, y ∉ A
=, ≠	Is (not) equal to
≥, ≤, <, >	Other comparison operators
⊆	Is a subset of	A ⊆ B
⊇	Is a superset of	A ⊇ B
⊂	Is a proper subset of	A ⊂ B
⊃	Is a proper superset of	A ⊃ B
∪	Union	A ∪ B
∩	Intersect	A ∩ B
−	Difference	A − B
÷	Symmetric difference	A ÷ B
×	Cartesian product	A × B
⊗	Natural join	A ⊗ B
⊘	The empty set
( ; )	Ordered pair	(EMPNO; 102)
⋄	Function composition	f⋄g
⋄⋄	Attribute renaming	T⋄⋄g
dom	Domain of a function	dom(F)
rng	Range of a function	rng(F)
π1	First coordinate of a pair	π1(a;b)
π2	Second coordinate of a pair	π2(a;b)
N	The set of natural numbers
Z	The set of all integers
↓	Limitation of a tuple	t↓{...}
⇓	Projection of a table	T⇓{...}
℘	Powerset of a set	℘A, ℘{...}
П	Product of a set function	П(F)
#	Cardinality of a set	#A, #{...}
SUM	Sum (of f over A)	SUMx∈A: f(x)
AVG	Average (of f over A)	AVGx∈A: f(x)
MAX	Maximum (of f over A)	MAXx∈A: f(x)
MIN	Minimum (of f over A)	MINx∈A: f(x)
	Choose operator	S, {a}

Table B-2. Mathematical Symbols Related to Logic