p441fig12.38 The LTM Invariance Principle is realized if the relative sizes of the inputs to the list chunk level stay the same as more items are stored in working memory.  This property, in turn, follows from shunting previously stored working memory activities when a ne4w item occurs.<BR>||  LTM Invariance principle.  Choose STM activities so that newly stored STM activities may alter the size of old STM activities without recoding their LTM patterns.  In particular: New events do not change the relative activities of past event sequences, but may reduce their absolute activites.  Why? Bottom-up adaptive filtering uses dot products: T(j) = sum[i=1 to n: x(i)*z(i,j) = total input to v(j).  The relative sizes of inputs to coding nodes v(j) are preserved.  x(i) -> w*x(i), 0 < w <= 1,  leaves all past ratios T(j)/T(k) unchanged.