SequenceHold is an attribute that specifies that Sequence objects appearing in the arguments of a function should not automatically be flattened out.

SyntaxQ["string"] returns True if the string corresponds to syntactically correct input for a single Mathematica expression, and returns False otherwise.

When Mathematica cannot give you an explicit result for an integral, it leaves the integral in a symbolic form. It is often useful to manipulate this symbolic form. ...

In some cases you may need to specify pattern sequences that are more intricate than things like x__ or x..; for such situations you can use PatternSequence[p_1,p_2,…]. ...

Getting parts of lists. This gives a list of parts 1 and 3. Here is a nested list.

 

Mathematica 's extensive capabilities for presenting data, text, graphics, and dynamic elements in formatted tables give you control over all elements of layout and styling. ...

Hyperlink creates a hyperlink to a specified cell, notebook, or URL.

Baseline is a symbol that represents the baseline for purposes of alignment and positioning.

ComposeList[{f_1, f_2, ...}, x] generates a list of the form {x, f_1[x], f_2[f_1[x]], ...}.