In most cases, you want the head f of a Mathematica expression like f[x] to be a single symbol. There are, however, some important applications of heads that are not symbols. ...

GroupOrbits[group, {p_1, ...}] returns the orbits of the points p_i under the action of the elements of group.GroupOrbits[group, {p_1, ...}, f] finds the orbits under the ...

ChessboardDistance[u, v] gives the chessboard, Chebyshev, or sup norm distance between vectors u and v.

These "How tos" give step-by-step instructions for common tasks related to algebraic computation in Mathematica .

Bookmarks is an option for Manipulate and related functions that gives a list of bookmark settings.

Continue[] exits to the nearest enclosing Do, For, or While in a procedural program.

LatticeReduce[{v_1, v_2, ...}] gives a reduced basis for the set of vectors v_i.

NotebookClose[notebook] closes the notebook corresponding to the specified notebook object. NotebookClose[] closes the current evaluation notebook.

WordSeparators is an option for Read, Find, and related functions that specifies the list of strings to be taken as delimiters for words.

ArrayQ[expr] gives True if expr is a full array or a SparseArray object, and gives False otherwise. ArrayQ[expr, patt] requires expr to be a full array with a depth that ...