Simplistically, a mathematical expression that is (at least locally) representable as a convergent power series on an open interval (in the Real Domain – the issue is more complex in the…Complex…Domain). Being expressed as a convergent power series means that the function is infinitely differentiable, therefore its value in the region around any given point can be calculated from those derivatives if they can somehow be evaluated.
This concept is important to verification because non-analytic Engineering relationships that are to be verified by Analysis will typically require numerical methods based on something other than (or in addition to) mere integration (e.g., Simulation), and carefully selected “anchor points” of validating test 1. They also tend to be quite specific to the design.
Footnotes- Which, if the analytic functions being verified are only piece-wise differentiable, must be selected in the specific locales of interest.[↩]