And
(Built-in Mathematica Symbol) e_1 && e_2 && ... is the logical AND function. It evaluates its arguments in order, giving False immediately if any of them are False, and True if they are all True.
AppellF1[a, b_1, b_2, c, x, y] is the Appell hypergeometric function of two variables F_1 (a; b_1, b_2; c; x, y).
ArcCsc
(Built-in Mathematica Symbol) ArcCsc[z] gives the arc cosecant csc -1 (z) of the complex number z.
ArcSinh
(Built-in Mathematica Symbol) ArcSinh[z] gives the inverse hyperbolic sine sinh -1 (z) of the complex number z.
ArcTan
(Built-in Mathematica Symbol) ArcTan[z] gives the arc tangent tan -1 (z) of the complex number z. ArcTan[x, y] gives the arc tangent of y/x, taking into account which quadrant the point (x, y) is in.
Assuming[assum, expr] evaluates expr with assum appended to $Assumptions, so that assum is included in the default assumptions used by functions such as Refine, Simplify, and ...
BesselJ
(Built-in Mathematica Symbol) BesselJ[n, z] gives the Bessel function of the first kind J_n (z).
Erfi
(Built-in Mathematica Symbol) Erfi[z] gives the imaginary error function erf(i z)/i.
HoldAll
(Built-in Mathematica Symbol) HoldAll is an attribute which specifies that all arguments to a function are to be maintained in an unevaluated form.
InverseSurvivalFunction[dist, q] gives the inverse of the survival function for the symbolic distribution dist as a function of the variable q.