Negligible variation and the change of variables theorem Vermont RutherfoordY. Sagher 26A3626A3926A4626A30change of variablesnegligible variationabsolute continuityHK integralgauge integral In this note we prove a necessary and sufficient condition for the change of variables formula for the HK integral, with implications for the change of variables formula for the Lebesgue integral. As a corollary, we obtain a necessary and sufficient condition for the Fundamental Theorem of Calculus to hold for the HK integral. Indiana University Mathematics Journal 2012 text pdf 10.1512/iumj.2012.61.4532 10.1512/iumj.2012.61.4532 en Indiana Univ. Math. J. 61 (2012) 31 - 44 state-of-the-art mathematics http://iumj.org/access/