| "lg x" is short for "logarithm of x with the base 2".
"Celling" should indeed be "ceiling". "Ceiling" is a function that takes a real number and returns an integer, in the following rule:
ceiling( x ) = min{ n : n >= x & n is an integer }
For example, ceiling( pi ) = 4, ceiling( -pi ) = -3
"Floor" is a function defined as:
floor( x ) = max{ n : n <= x & n is an integer }
For example, floor( pi ) = 3, floor( -pi ) = -4
Of course, floor( 3 ) = 3, and ceiling( 3 ) = 3. |