NonNegative (Built-in Mathematica Symbol)

NonNegative[x] gives True if x is a non-negative number.

NonPositive (Built-in Mathematica Symbol)

NonPositive[x] gives True if x is a non-positive number.

Positive (Built-in Mathematica Symbol)

Positive[x] gives True if x is a positive number.

Primes (Built-in Mathematica Symbol)

Primes represents the domain of prime numbers, as in x \[Element] Primes.

Trig (Built-in Mathematica Symbol)

Trig is an option for various polynomial manipulation functions that specifies whether trigonometric functions should be treated like polynomial elements.

Reals (Built-in Mathematica Symbol)

Reals represents the domain of real numbers, as in x \[Element] Reals.

Rearrange the Terms of a Polynomial (Mathematica How To)

Mathematica provides many functions to group terms in a polynomial, extract and sort the monomials, display them in various ways, and even process them as arbitrary ...

Rationals (Built-in Mathematica Symbol)

Rationals represents the domain of rational numbers, as in x \[Element] Rationals.

Check the Results of DSolve (Mathematica How To)

While DSolve usually returns the correct solution to a differential equation it is given, it is common practice to verify the solution returned by any differential equation ...

Algebraics (Built-in Mathematica Symbol)

Algebraics represents the domain of algebraic numbers, as in x \[Element] Algebraics.