Glossary:Stability increase matrix

stability increase matrix (SInc matrix; SInc[])

the matrix that represents the function of interval/stability increase in SuperMemo algorithm. For any item at any time, the increase in stability depends on:

1. current stability,
2. current retrievability, and
3. current item difficulty.

This function can be inspected using: Toolkit : Memory : 4D Graphs : Stability in SuperMemo. The SInc[] matrix can be considered an extension of the OF matrix (from older SuperMemos) into the dimension of retrievability. This means that the new SuperMemo algorithm can handle any repetition at any time, including freshly reviewed items, as well as long-neglected items. Retrievability is the dimension that reflects the time that has elapsed since the last repetition relative to the optimum interval