back out to the original well the things that's possible well okay let's see imagine you want to compress every possible to compress every possible possible bitstream they ever encounter okay so that's not possible no longer we can do this what's the intuition that should be simple we'll do a proof by contradiction suppose you have a universal data compression algorithm you that can compress every bit streams no matter what your feet it is gonna make it less bits and then go to decompress it back out later to the original okay now given