Mathematica allows almost every aspect of sessions to be customized, under full programmatic control.
Type the expression that will have an underscript. Type x. Create an underscript by pressing the Control key and the 4 key at the same time.
PathGraph[{v_1, v_2, ...}] yields a path with vertices v_i and edges between v_i and v i +\[ThinSpace]1 .PathGraph[{e_1, e_2, ...}] yields a path with edges ...
TreeGraph[{v_1, v_2, ...}, {u_1, u_2, ...}] yields a tree where u_i is the predecessor of v_i.TreeGraph[{e_1, e_2, ...}] yields a tree with edges e_j.TreeGraph[{v_1, v_2, ...
Checkbox[x] represents a checkbox with setting x, displayed as CheckboxBox[True] when x is True and CheckboxBox[False] when x is False. Checkbox[Dynamic[x]] takes the setting ...
Grid
(Built-in Mathematica Symbol) Grid[{{expr_11, expr_12, ...}, {expr_21, expr_22, ...}, ...}] is an object that formats with the expr_ij arranged in a two-dimensional grid.
The world's largest integrated web of mathematical capabilities and algorithms
AnimationRepetitions is an option to Animate and related functions that specifies how many times the animation they create runs before stopping.
Arithmetic Numerical Mathematics in Mathematica The Uncertainties of Numerical Mathematics
Widget["Table"] represents a table.