Suggested Text Notation
This is a list of suggested notation to use when you are writing a simple text file with mathematics in it.
General math
x1, x2, xn - x with subscripts 1, 2, n a /= b - a not equal to b a <= b - a smaller than or equal to b a >= b - a greater than or equal to b oo - infinity INF - infinity
Sets
0 - empty set
A U B - A union B
A /\ B - A intersection B ("snitt")
A snitt B - A intersection B ("snitt")
A \ B - A difference B
A -> B - functions from A to B
A x B - Cartesian product of A and B
|B - |B, set of booleans {0,1}
|N - |N, natural numbers
|Z - |Z, integer numbers ("heltal")
|N+, |Z+ - |N+, |Z+, positive integers ("positiva heltal")
|Q - |Q, rational numbers
|R - |R, real numbers
A <= B - A subset of B A < B - A strict subset of B
Note: Please add spaces ("mellanslag") between operators and their arguments. So: write A U B and not AUB.
Note: When you use x for Cartesian product, please do not use x as a variable name at the same time.
Functions
f : |N -> |N - f goes from |N to |N
x |-> 2x - the function that takes x to 2x
a*b - multiplication
a^b - a to the power of b ("a upphöjd till b" / "potens")
f . g - function composition of f and g
Logic
p ^ q - conjunction
p /\ q - conjunction
p & q - conjunction
p v q - disjunction
p \/ q - disjunction
p -> q - implication
p <-> q - equivalence
~p - negation ("inte")
not p - negation ("inte")
inte p - negation ("inte")
ALL x : P(x) - for all x, such that P(x)
EXI x : P(x) - exists x, such that P(x) ("det finns ett x")
FINNS x : P(x) - exists x, such that P(x) ("det finns ett x")
Note: When you use v for disjunction, please do not use v as a variable name at the same time.
Sums
SUM(i=0,n) ai - the sum of all ai for i from 0 to n oo - infinity INF - infinity