Point estimation theory constructs initial conditions that provide safe convergence of a numerical root-finding algorithm for an equation
.
It treats convergence conditions and the domain of convergence using only information
about 
at the initial point 
(Petković et al. 1997, p. 1). An initial
point that provides safe convergence of Newton's method
is called an approximate zero.
Point estimation theory should not be confused with point estimators of probability theory.
