双等比差数列及其性质四川省富顺师范李显权文献［１］、［２］分别介绍了“双等比数列”和“双等差数列”，这无疑是对等比、等差数列的又一种拓广．然而进一步地，我们又自然会联想到，上述双等比、双等差数列之间有无什么联系呢？本文将指出，它们统一于下面的双等比差... Double-Differential-Difference Sequences and Their Properties Sichuan Fushun Normal University Li Xian-quan [1] and [2] respectively introduced the “Double-Digitometric Sequences” and “Double-difference Sequences”, which is undoubtedly the same for equal-ratio and arithmetic-difference sequences. A broad extension. However, further, we naturally think that there is no connection between the above double-difference and double-difference series. This article will point out that they are unified in the following double ratio difference...