On the metric properties of dynamic time warping
Francisco Casacuberta, Enrique Vidal, H. Rulot · IEEE Transactions on Acoustics Speech and Signal Processing · 1987
Recently, some new and promising methods have been proposed to reduce the number of Dynamic Time Warping (DTW) computations in Isolated Word Recognition. For these methods to be properly applicable, the verification of the Triangle Inequality (TI) by the DTW-based Dissimilarity Measure utilized seems to be an important prerequisite.