VertexCount[g] gives a count of the number of vertices in the graph g.VertexCount[g, patt] gives a count of the number of vertices that match the pattern patt.

GraphDifference[g_1, g_2] gives the graph difference of the graphs g_1 and g_2.

D[f, x] gives the partial derivative \[PartialD]f/\[PartialD]x. D[f, {x, n}] gives the multiple derivative \[PartialD]^n f/\[PartialD]x^n. D[f, x, y, ...] differentiates f ...

Mathematica provides a general mechanism for specifying constraints on patterns. All you need to do is to put /;condition at the end of a pattern to signify that it applies ...

Permutations are basic elements in algebra. They have a natural non-commutative product (as matrices do as well), and hence can encode highly nontrivial structures in a ...

NullSpace[m] gives a list of vectors that forms a basis for the null space of the matrix m.

Head[expr] gives the head of expr.

Most of the documentation provided for Mathematica is concerned with explaining what Mathematica does, not how it does it. But the purpose of this is to say at least a little ...

Count[list, pattern] gives the number of elements in list that match pattern. Count[expr, pattern, levelspec] gives the total number of subexpressions matching pattern that ...

VectorScale is an option to VectorPlot, ListVectorPlot, and related functions that determines the length and arrowhead size of field vectors that are drawn.