Notation

⨳

after a contradiction

⊆

subset (could be the same)

⊄

not a subset of

∉

not an element of

⊂

proper subset

∈

element of (single items only)

∃

there exists

ℚ

rationals (quotients)

is n(A) allowed

yes

∅

empty set

ℤ ₀⁺

non negative integars (includes 0)

closed interval symbol and meaning

[ ] weak inequalities

open interval symbol and meaning

( ) strict ineqaulities

∏ like a summation sign meaning

multiply all the terms from the lower limit to the upper limit

f : x → y

function f maps the element x to the element y

x with a dot above it

derivative of x with respect to t

E(X)

expectation of the random variable X

sample variance

s