NumberFieldSignature[a] gives the signature of the field \[DoubleStruckCapitalQ][a] generated by the algebraic number a.
Numerator[expr] gives the numerator of expr.
Outer
(Built-in Mathematica Symbol) Outer[f, list_1, list_2, ...] gives the generalized outer product of the list_i, forming all possible combinations of the lowest-level elements in each of them, and feeding ...
OverscriptBox[x, y] is the low-level box representation for OverscriptBox[x, y] in notebook expressions.
PaletteNotebook[{cell_1, cell_2, ...}] represents a palette notebook that can be manipulated by the Mathematica front end.
ParagraphSpacing is an option for Cell, StyleBox, and Style that specifies how much extra space to leave between successive paragraphs of text.
ParallelProduct[expr, {i, i_max}] evaluates the product \[Product]i = 1 i_max expr in parallel.ParallelProduct[expr, {i, i_min, i_max}] starts with i = ...
ParallelSum[expr, {i, i_max}] evaluates in parallel the sum \[Sum]i = 1 i_max expr.ParallelSum[expr, {i, i_min, i_max}] starts with i = i min.ParallelSum[expr, {i, i_min, ...
PaulWavelet[] represents a Paul wavelet of order 4.PaulWavelet[n] represents a Paul wavelet of order n.
PermutationPower[perm, n] gives the n\[Null]^th permutation power of the permutation perm.