Current intermittent demand inventory control models assume that the interval is memoryless: probability of observing a positive does not depend on time since last occurred. Contrarily, several forecasting contributions suggest intervals contain more distributional information. We find data M5 competition confirms this. Therefore, we propose an model explicitly uses full distributions sizes and...

the notion of $f$-derivations of up-algebras is introduced, some useful examples are discussed, and related properties are investigated. moreover, we show that the fixed set and the kernel of $f$-derivations are up-subalgebras of up-algebras,and also give examples to show that the two sets are not up-ideals of up-algebras in general.