1 technological change within nested hierarchies the case of information technology sector by jeffrey l funk professor hitotsubashi university institute innovation research 2 naka kunitachi tokyo 186 8603 japan telephone 81 42 580 8430 facsimile 8410 iir hit u ac jp title abstract this paper demonstrates a model that addresses sources and timing discontinuities using data from it emphasizes subsystems product design customer choice tradeoffs incremental improvements at lower levels in hierarchy defines both physical relationships between parallel firms where are defined each level one drive changes higher adjacent thus require to rethink for their
