At the core of Mathematica is the foundational idea that everything —data, programs, formulas, graphics, documents—can be represented as symbolic expressions. And it is this ...

NHoldRest is an attribute which specifies that all but the first argument to a function should not be affected by N.

Constant is an attribute that indicates zero derivative of a symbol with respect to all parameters.

NumericFunction is an attribute that can be assigned to a symbol f to indicate that f[arg_1, arg_2, ...] should be considered a numeric quantity whenever all the arg_i are ...

NHoldAll is an attribute which specifies that none of the arguments to a function should be affected by N.

RuntimeAttributes is an option for Compile that specifies attributes for the compiled function it creates.

ClearAll[symb_1, symb_2, ...] clears all values, definitions, attributes, messages, and defaults associated with symbols. ClearAll["form_1 ", "form_2", ...] clears all ...

Principles of Evaluation Reducing Expressions to Their Standard Form Attributes

Mathematica's unified symbolic architecture immediately allows it to perform structural transformations not only on objects like lists, but also on general symbolic ...

When you set a value to a symbol, that value will be used for the symbol for the entire Mathematica session. Since symbols no longer in use can introduce unexpected errors ...