Composition[f_1, f_2, f_3, ...] represents a composition of the functions f_1, f_2, f_3, ....
Integers represents the domain of integers, as in x \[Element] Integers.
InterpolatingPolynomial[{f_1, f_2, ...}, x] constructs an interpolating polynomial in x which reproduces the function values f_i at successive integer values 1, 2, ... of x. ...
MapAll
(Built-in Mathematica Symbol) MapAll[f, expr] or f //@ expr applies f to every subexpression in expr.
Four underlying types of numbers are built into Mathematica. Intrinsic types of numbers in Mathematica. Rational numbers always consist of a ratio of two integers, reduced to ...
Root::deg
Root::rnv
Root::mdeg
Root::npoly
Root::var