≡y . r is equivalent to(or identical with) x≠y c is not equivalent to(or identical with)y ter th a is greater than or equal to y <y x≤y .r is less than or equal to y 0<x<1 zero is less than r is less than 1 0≤x≤1 zero is less than or equal to a is less than or equal to 1 mod a/ modulus a squared/a(raised) to the power 2 to the fourth/a to the power four r to the nth/a to the power n to the(power) minus n (square)root a/ the square root of a cube root( fourth root nth root(of) (x+y) r plus y all squared r over y all squared m factorial ci/a subscript i/a suffix i/a sub i the sum from i equals one to n ai/ the sum as i runs from 1 to n of the a =1 4. Linear algebra the norm(or modulus)of a OA OA/ vector OA OA OA/ the length of the segment OA 4 a ti the transpose of A A inverse/ the inverse of Ax ≡ y x is equivalent to (or identical with) y x 6≡ y x is not equivalent to (or identical with) y x > y x is greater than y x ≥ y x is greater than or equal to y x < y x is less than y x ≤ y x is less than or equal to y 0 < x < 1 zero is less than x is less than 1 0 ≤ x ≤ 1 zero is less than or equal to x is less than or equal to 1 |x| mod x / modulus x x 2 x squared / x (raised) to the power 2 x 3 x cubed x 4 x to the fourth / x to the power four x n x to the nth / x to the power n x −n x to the (power) minus n √ x (square) root x / the square root of x √3 x cube root (of) x √4 x fourth root (of) x √n x nth root (of) x (x + y) 2 x plus y all squared ³x y ´2 x over y all squared n! n factorial xˆ x hat x¯ x bar x˜ x tilde xi xi / x subscript i / x suffix i / x sub i Xn i=1 ai the sum from i equals one to n ai / the sum as i runs from 1 to n of the ai 4. Linear algebra kxk the norm (or modulus) of x −−→OA OA / vector OA OA OA / the length of the segment OA AT A transpose / the transpose of A A−1 A inverse / the inverse of A 2