ABSTRACT
To build a corresponding mathematical model let us suppose that the random variables
Define Sn = n = 1,2, — Then the points
So = 0,Si,S2, • • • ,Sn, . . . ,
So, if one observes the system at the instant t > 0 then Y~(t) is the time passed from the last replacement of the element; T + (t) is the time up to the next replacement and Y(t) is the total time of work
Denote by
To formulate the results we have to discriminate between F lattice (concentrated on some set {c, 2c, 3c ,. . . } with c > 0 maximal, then c is called the span of F ) and non-lattice. Suppose that F is non lattice. (The analogs results are valid in lattice case too.)
ii.
