Error bound
= Error bound
{title2=$|\widetilde f-f|\leq\varepsilon$}
An <error bound> is an established <upper bound> on a specified <approximation error>, on a stated domain and under stated assumptions. A numerical comparison at selected points can test an approximation but does not by itself establish a bound throughout that domain. An <absolute error> bound controls $|\widetilde f-f|$; a <relative error> bound additionally specifies the reference scale.