DirectedGraph[g] gives a directed graph from the undirected graph g.DirectedGraph[g, conv] gives a directed graph using the conversion conv.

DirectedGraphQ[g] yields True if the graph g is a directed graph and False otherwise.

DirichletConvolve[f, g, n, m] gives the Dirichlet convolution of the expressions f and g.

DirichletTransform[expr, n, s] gives the Dirichlet transform of expr with respect to n.

DiscreteIndicator[x, x_1, {u_1, u_2, ...}] yields the discrete indicator function, equal to 1 if x = x_1 and 0 if x = u_i for any i.

Dispatch[{lhs_1 -> rhs_1, lhs_2 -> rhs_2, ...}] generates an optimized dispatch table representation of a list of rules. The object produced by Dispatch can be used to give ...

DisplayForm[expr] prints with low-level boxes inside expr shown in explicit two-dimensional or other form.

DistributedContexts is an option for various parallel computing functions that specifies which definitions for symbols appearing in an expression should be distributed to all ...

DumpSave["file.mx", symbol] writes definitions associated with a symbol to a file in internal Mathematica format. DumpSave["file.mx", " context`"] writes out definitions ...

DynamicWrapper[e, expr] represents an object that displays as e, but dynamically updates the expression expr whenever that object is visible on screen.