| rowspan="3" align=center| Symbol | align=left|Name | rowspan="3" |Explanation | rowspan="3" |Example |
| lign=center|Should be read as |
| lign=right|Category |
| rowspan=3 bgcolor=#d0f0d0 align=center| = | |equality | rowspan=3|x = y means x and y represent the same thing or value. | rowspan=3|1 + 1 = 2 |
| lign=center|is equal to; equals |
| lign=right|everywhere |
| rowspan=3 bgcolor=#d0f0d0 align=center| ≠ | |Inequation | rowspan=3| x ≠ y means that x and y do not represent the same thing or value. | rowspan=3|1 ≠ 2 |
| lign=center|is not equal to; does not equal |
| lign=right|everywhere |
| rowspan=3 bgcolor=#d0f0d0 align=center| + | addition | rowspan=3|4 + 6 means the sum of 4 and 6. | rowspan=3|2 + 7 = 9 |
| lign=center|plus |
| lign=right|arithmetic |
| rowspan=9 bgcolor=#d0f0d0 align=center| − | subtraction | rowspan=3|9 − 4 means the subtraction of 4 from 9. | rowspan=3|8 − 3 = 5 |
| lign=center|minus |
| lign=right|arithmetic |
| a href="/encyclopedia/negative-and-non-negative-numbers" title="negative and non-negative numbers">negative sign | rowspan=3|−3 means the negative of the number 3. | rowspan=3|−(−5) = 5 |
| lign=center|negative |
| lign=right|arithmetic |
| a href="/encyclopedia/set-theoretic-complement" title="set theoretic complement">set theoretic complement | rowspan=3|A − B means the set that contains all the elements of A that are not in B. | rowspan=3|{1,2,4} − {1,3,4} = {2} |
| lign=center|minus; without |
| lign=right|set theory |
| rowspan=6 bgcolor=#d0f0d0 align=center| × | multiplication | rowspan=3|3 × 4 means the multiplication of 3 by 4. | rowspan=3|7 × 8 = 56 |
| lign=center|times |
| lign=right|arithmetic |
| a href="/encyclopedia/Cartesian-product" title="Cartesian product">Cartesian product | rowspan=3|X×Y means the set of all ordered pairs with the first element of each pair selected from X and the second element selected from Y. | rowspan=3|{1,2} × {3,4} = {(1,3),(1,4),(2,3),(2,4)} |
| lign=center|the Cartesian product of and ; the direct product of and |
| lign=right|set theory |
| rowspan=3 bgcolor=#d0f0d0 align=center| ÷
/ | |division | rowspan=3|6 ÷ 3 or 6/3 means the division of 6 by 3. | rowspan=3|2 ÷ 4 = .5 12/4 = 3 |
| lign=center|divided by |
| lign=right|arithmetic |
| rowspan=3 bgcolor=#d0f0d0 align=center| ⇒
→
⊃ | |material implication | rowspan=3|A ⇒ B means if A is true then B is also true; if A is false then nothing is said about B.
→ may mean the same as ⇒, or it may have the meaning for functions given below.
⊃ may mean the same as ⇒, or it may have the meaning for superset given below. | rowspan=3|x = 2 ⇒ x2 = 4 is true, but x2 = 4 ⇒ x = 2 is in general false (since x could be −2). |
| lign=center|implies; if .. then |
| lign=right|propositional logic |
| rowspan=3 bgcolor=#d0f0d0 align=center| ⇔
↔ | |material equivalence | rowspan=3|A ⇔ B means A is true if B is true and A is false if B is false. | rowspan=3|x + 5 = y +2 ⇔ x + 3 = y |
| lign=center|if and only if; iff |
| lign=right|propositional logic |
| rowspan=3 bgcolor=#d0f0d0 align=center| ¬
˜ | |logical negation | rowspan=3|The statement ¬A is true if and only if A is false.
A slash placed through another operator is the same as "¬" placed in front. | rowspan=3|¬(¬A) ⇔ A x ≠ y ⇔ ¬(x = y) |
| lign=center|not |
| lign=right|propositional logic |
| rowspan=3 bgcolor=#d0f0d0 align=center| ∧ | |logical conjunction or meet in a lattice | rowspan=3|The statement A ∧ B is true if A and B are both true; else it is false. | rowspan=3|n < 4 ∧ n >2 ⇔ n = 3 when n is a natural number. |
| lign=center|and |
| lign=right|propositional logic, lattice theory |
| rowspan=3 bgcolor=#d0f0d0 align=center| ∨ | |logical disjunction or join in a lattice | rowspan=3|The statement A ∨ B is true if A or B (or both) are true; if both are false, the statement is false. | rowspan=3|n ≥ 4 ∨ n ≤ 2 ⇔ n ≠ 3 when n is a natural number. |
| lign=center|or |
| lign=right|propositional logic, lattice theory |
rowspan=3 bgcolor=#d0f0d0 align=center|
⊕
⊻ | exclusive or | rowspan=3| is true when either A or B is true, but not when both are true. | rowspan=3| (¬A) A is always true, A A is always false. |
| lign=center|xor |
| lign=right|propositional logic, Boolean algebra |
| rowspan=3 bgcolor=#d0f0d0 align=center| ∀ | |universal quantification | rowspan=3|∀ x: P(x) means P(x) is true for all x. | rowspan=3|∀ n ∈ N: n2 ≥ n |
| lign=center|for all; for any; for each |
| lign=right|predicate logic |
| rowspan=3 bgcolor=#d0f0d0 align=center| ∃ | |existential quantification | rowspan=3|∃ x: P(x) means there is at least one x such that P(x) is true. | rowspan=3|∃ n ∈ N: n + 5 = 2n |
| lign=center|there exists |
| lign=right|predicate logic |
| rowspan=3 bgcolor=#d0f0d0 align=center| :=
≡
:⇔ | |definition | rowspan=3|x := y or x ≡ y means x is defined to be another name for y (but note that ≡ can also mean other things, such as congruence).
P :⇔ Q means P is defined to be logically equivalent to Q. | rowspan=3|cosh x := (1/2)(exp x + exp (−x))
A XOR B :⇔ (A ∨ B) ∧ ¬(A ∧ B) |
| lign=center|is defined as |
| lign=right|everywhere |
| rowspan=3 bgcolor=#d0f0d0 align=center| { , } | |set brackets | rowspan=3|{a,b,c} means the set consisting of a, b, and c. | rowspan=3|N = {0,1,2,...} |
| lign=center|the set of ... |
| lign=right|set theory |
| rowspan=3 bgcolor=#d0f0d0 align=center| { : }
{ | } | |set builder notation | rowspan=3|{x : P(x)} means the set of all x for which P(x) is true. {x | P(x)} is the same as {x : P(x)}. | rowspan=3|{n ∈ N : n2 < 20} = {0,1,2,3,4} |
| lign=center|the set of ... such that ... |
| lign=right|set theory |
rowspan=3 bgcolor=#d0f0d0 align=center|
{}
| empty set | rowspan=3| means the set with no elements. {} means the same. | rowspan=3|{n ∈ N : 1 < n2 < 4} = |
| lign=center| the empty set |
| lign=right|set theory |
| rowspan=3 bgcolor=#d0f0d0 align=center| ∈
∉ | |set membership | rowspan=3|a ∈ S means a is an element of the set S; a ∉ S means a is not an element of S. | rowspan=3|(1/2)−1 ∈ N
2−1 ∉ N |
| lign=center|is an element of; is not an element of |
| lign=right|everywhere, set theory |
| rowspan=3 bgcolor=#d0f0d0 align=center| ⊆
⊂ | |subset | rowspan=3|A ⊆ B means every element of A is also element of B.
A ⊂ B means A ⊆ B but A ≠ B. | rowspan=3|A ∩ B ⊆ A; Q ⊂ R |
| lign=center|is a subset of |
| lign=right|set theory |
| rowspan=3 bgcolor=#d0f0d0 align=center| ⊇
⊃ | |superset | rowspan=3|A ⊇ B means every element of B is also element of A.
A ⊃ B means A ⊇ B but A ≠ B. | rowspan=3|A ∪ B ⊇ B; R ⊃ Q |
| lign=center|is a superset of |
| lign=right|set theory |
| rowspan=3 bgcolor=#d0f0d0 align=center| ∪ | |set theoretic union | rowspan=3|A ∪ B means the set that contains all the elements from A and also all those from B, but no others. | rowspan=3|A ⊆ B ⇔ A ∪ B = B |
| lign=center|the union of ... and ...; union |
| lign=right|set theory |
| rowspan=3 bgcolor=#d0f0d0 align=center| ∩ | |set theoretic intersection | rowspan=3|A ∩ B means the set that contains all those elements that A and B have in common. | rowspan=3|{x ∈ R : x2 = 1} ∩ N = {1} |
| lign=center|intersected with; intersect |
| lign=right|set theory |
| rowspan=3 bgcolor=#d0f0d0 align=center| \ | |set theoretic complement | rowspan=3|A \ B means the set that contains all those elements of A that are not in B. | rowspan=3|{1,2,3,4} \ {3,4,5,6} = {1,2} |
| lign=center|minus; without |
| lign=right|set theory |
| rowspan=6 bgcolor=#d0f0d0 align=center| ( ) | |function application | rowspan=3|f(x) means the value of the function f at the element x. | rowspan=3|If f(x) := x2, then f(3) = 32 = 9. |
| lign=center|of |
| lign=right|set theory |
| precedence grouping | rowspan=3| Perform the operations inside the parentheses first. | rowspan=3|(8/4)/2 = 2/2 = 1, but 8/(4/2) = 8/2 = 4. |
| lign=center| |
| lign=right|everywhere |
| rowspan=3 bgcolor=#d0f0d0 align=center| f:X→Y | |function arrow | rowspan=3|f: X → Y means the function f maps the set X into the set Y. | rowspan=3|Let f: Z → N be defined by f(x) = x2. |
| lign=center|from ... to |
| lign=right|functions |
rowspan=3 bgcolor=#d0f0d0 align=center|
N
ℕ | |natural numbers | rowspan=3|N means {0,1,2,3,...}, but see the article on natural numbers for a different convention. | rowspan=3|{|a| : a ∈ Z} = N |
| lign=center|N |
| lign=right|numbers |
rowspan=3 bgcolor=#d0f0d0 align=center|
Z ℤ | integers | rowspan=3|Z means {...,−3,−2,−1,0,1,2,3,...}. | rowspan=3|{a : |a| ∈ N} = Z |
| lign=center|Z |
| lign=right|numbers |
rowspan=3 bgcolor=#d0f0d0 align=center|
Q ℚ | rational numbers | rowspan=3|Q means {p/q : p,q ∈ Z, q ≠ 0}. | rowspan=3|3.14 ∈ Q
π ∉ Q |
| lign=center|Q |
| lign=right|numbers |
rowspan=3 bgcolor=#d0f0d0 align=center|
R ℝ | real numbers | rowspan=3|R means {limn→∞ an : ∀ n ∈ N: an ∈ Q, the limit exists}. | rowspan=3|π ∈ R
√(−1) ∉ R |
| lign=center|R |
| lign=right|numbers |
rowspan=3 bgcolor=#d0f0d0 align=center|
C ℂ | complex numbers | rowspan=3|C means {a + bi : a,b ∈ R}. | rowspan=3|i = √(−1) ∈ C |
| lign=center|C |
| lign=right|numbers |
| rowspan=3 bgcolor=#d0f0d0 align=center| <
> | |strict inequality | rowspan=3|x < y means x is less than y.
x > y means x is greater than y. | rowspan=3|x < y ⇔ y > x |
| lign=center|is less than, is greater than |
| lign=right|partial orders |
| rowspan=3 bgcolor=#d0f0d0 align=center| ≤
≥ | |inequality | rowspan=3|x ≤ y means x is less than or equal to y.
x ≥ y means x is greater than or equal to y. | rowspan=3|x ≥ 1 ⇒ x2 ≥ x |
| lign=center|is less than or equal to, is greater than or equal to |
| lign=right|partial orders |
| rowspan=3 bgcolor=#d0f0d0 align=center| √ | |square root | rowspan=3|√x means the positive number whose square is x. | rowspan=3|√(x2) = |x| |
| lign=center|the principal square root of; square root |
| lign=right|real numbers |
| rowspan=3 bgcolor=#d0f0d0 align=center| ∞ | |infinity | rowspan=3|∞ is an element of the extended number line that is greater than all real numbers; it often occurs in limits. | rowspan=3|limx→0 1/|x| = ∞ |
| lign=center|infinity |
| lign=right|numbers |
| rowspan=3 bgcolor=#d0f0d0 align=center| π | pi | rowspan=3|π means the ratio of a circle's circumference to its diameter. | rowspan=3|A = πr² is the area of a circle with radius r |
| lign=center|pi |
| lign=right|Euclidean geometry |
| rowspan=3 bgcolor=#d0f0d0 align=center| ! | |factorial | rowspan=3|n! is the product 1×2×...×n. | rowspan=3|4! = 1 × 2 × 3 × 4 = 24 |
| lign=center|factorial |
| lign=right|combinatorics |
| rowspan=3 bgcolor=#d0f0d0 align=center| | | | |absolute value | rowspan=3| |x| means the distance in the real line (or the complex plane) between x and zero. | rowspan=3| |a + bi| = √(a2 + b2) |
| lign=center|absolute value of |
| lign=right|numbers |
| rowspan=3 bgcolor=#d0f0d0 align=center| || || | |norm | rowspan=3| ||x|| is the norm of the element x of a normed vector space. | rowspan=3| ||x+y|| ≤ ||x|| + ||y|| |
| lign=center|norm of; length of |
| lign=right|functional analysis |
| rowspan=3 bgcolor=#d0f0d0 align=center| ∑ | |summation | rowspan=3|∑k=1n ak means a1 + a2 + ... + an. | rowspan=3|∑k=14 k2 = 12 + 22 + 32 + 42 = 1 + 4 + 9 + 16 = 30 |
| lign=center|sum over ... from ... to ... of |
| lign=right|arithmetic |
| rowspan=6 bgcolor=#d0f0d0 align=center| ∏ | |product | rowspan=3|∏k=1n ak means a1a2···an. | rowspan=3|∏k=14 (k + 2) = (1 + 2)(2 + 2)(3 + 2)(4 + 2) = 3 × 4 × 5 × 6 = 360 |
| lign=center|product over ... from ... to ... of |
| lign=right|arithmetic |
| Cartesian product | rowspan=3|∏i=0nYi means the set of all (n+1)-tuples (y0,...,yn). | rowspan=3|∏n=13R = Rn |
| lign=center|the Cartesian product of; the direct product of |
| lign=right|set theory |
| rowspan=3 bgcolor=#d0f0d0 align=center| ∫ | |integral | rowspan=3|∫ab f(x) dx means the signed area between the x-axis and the graph of the function f between x = a and x = b. | rowspan=3|∫0b x2 dx = b3/3; ∫x2 dx = x3/3 |
| lign=center|integral from ... to ... of ... with respect to |
| lign=right|calculus |
| rowspan=3 bgcolor=#d0f0d0 align=center| f ' | |derivative | rowspan=3|f '(x) is the derivative of the function f at the point x, i.e., the slope of the tangent there. | rowspan=3|If f(x) = x2, then f '(x) = 2x and f ''(x) = 2 |
| lign=center|derivative of f; f prime |
| lign=right|calculus |
| rowspan=3 bgcolor=#d0f0d0 align=center| ∇ | |gradient | rowspan=3|∇f (x1, …, xn) is the vector of partial derivatives (df / dx1, …, df / dxn). | rowspan=3|If f (x,y,z) = 3xy + z² then ∇f = (3y, 3x, 2z) A transparent image for text is: Image:Del.gif (). |
| lign=center|del, nabla, gradient of |
| lign=right|calculus |
| rowspan=3 bgcolor=#d0f0d0 align=center| ∂ | |partial derivative | rowspan=3| With f (x1, …, xn), ∂f/∂xi is the derivative of f with respect to xi, with all other variables kept constant. | rowspan=3| If f(x,y) = x2y, then ∂f/∂x = 2xy |
| lign=center|partial derivative of |
| lign=right|calculus |
| rowspan=6 bgcolor=#d0f0d0 align=center| ⊥ | |perpendicular | rowspan=3|x ⊥ y means x is perpendicular to y; or more generally x is orthogonal to y. | rowspan=3| |
| lign=center|is perpendicular to |
| lign=right|orthogonality |
| bottom element | rowspan=3|x = ⊥ means x is the smallest element. | rowspan=3| |
| lign=center|the bottom element |
| lign=right|lattice theory |
| rowspan=3 bgcolor=#d0f0d0 align=center| ⊧ | |entailment | rowspan=3| means the sentence a entails the sentence b. Formal definition: if and only if, in every model in which a is true, b is also true. | rowspan=3| |
| lign=center|entails |
| lign=right|propositional logic, predicate logic |
| rowspan=3 bgcolor=#d0f0d0 align=center| ⊢ | |inference | rowspan=3|x y means y is derived from x. | rowspan=3| |
| lign=center|infers or is derived from |
| lign=right|propositional logic, predicate logic |
If some of these symbols are used in a Wikipedia article that is intended for beginners, it may be a good idea to include a statement like the following, (below the definition of the subject), in order to reach a broader audience: