<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jul 23, 2015, at 12:35 PM, Gavin Andresen <<a href="mailto:gavinandresen@gmail.com" class="">gavinandresen@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">There are lots of things we can do to decrease costs, and a lot of things have ALREADY been done (e.g. running a pruned full node).</span></div></blockquote></div><br class=""><div class="">I also wanted to point out I fully agree with you that there are still many optimizations we could do to reduce costs, and think many of these things are certainly worth doing. However, there’s only so much we can do in this regard. Sooner or later we still run up against theoretical limitations. These optimizations can reduce costs by some factor…but they are highly unlikely to overcome the Ω(n) validation complexity barring some major algorithmic breakthrough (and perhaps allowing for nondeterminism, perhaps accepting a negligible but finite error probability).</div></body></html>