Riffle[{e_1, e_2, ...}, x] gives {e_1, x, e_2, x, ...}. Riffle[{e_1, e_2, ...}, {x_1, x_2, ...}] gives {e_1, x_1, e_2, x_2, ...}. Riffle[list, x, n] yields a list in which ...

ContraharmonicMean[list] gives the contraharmonic mean of the values in list.ContraharmonicMean[list, p] gives the order p Lehmer contraharmonic mean.

You can tell a lot about what "type" of expression something is by looking at its head. Thus, for example, an integer has head Integer, while a list has head List. In a ...

NotebooksMenu is a global option that specifies which recently opened notebooks are listed under the File menu.

FromCoefficientRules[list, {x_1, x_2, ...}] constructs a polynomial from a list of rules for exponent vectors and coefficients.

GroupSetwiseStabilizer[group, {p_1, ..., p_n}] returns the subgroup of group for which the images of the points p_i are still in the list {p_1, ..., p_n}.

TakeWhile[list, crit] gives elements e_i from the beginning of list, continuing so long as crit[e_i] is True.

PartitionMap[f, list, n] applies f to list after partitioning into nonoverlapping sublists of length n. PartitionMap[f, list, n, d] applies f to sublists obtained by ...

AngleBracket[x, y, ...] displays as \[LeftAngleBracket]x, y, ...\[RightAngleBracket].

Definition[symbol] prints as the definitions given for a symbol.