The inverse hyperbolic secant sech^(-1) z, sometimes called the area hyperbolic secant and sometimes also denoted arcsech z, is the multivalued function that is the inverse function of the hyperbolic secant. The variants Arcsech z or Arsech z are sometimes used to refer to explicit principal values of the inverse hyperbolic secant, although this distinction is not always made. Worse yet, the notation arccsch z is sometimes used for the principal value, with Arcsech z being used for the multivalued function. Note that in the notation sech^(-1) z, sech z is the hyperbolic secant and the superscript -1 denotes an inverse function, not the multiplicative inverse.