To simplify, It’s saying, if the genome were a string of some length, for any possible byte b and byte position i, there exists a person whose genome has b at position i. Unlike normal character strings, there are only 20 or so valid characters (proteins) encoded by 3 “bytes” (nucleotides) each. So you’re looking at O(10 billion) values of (i, b) that would still keep the string well-formed in its 3-bytes-per-character encoding.
Most importantly, it’s not saying anything about having some bytes b1 and b2 at the ith and jth positions or any generalization thereof.
To simplify, It’s saying, if the genome were a string of some length, for any possible byte b and byte position i, there exists a person whose genome has b at position i. Unlike normal character strings, there are only 20 or so valid characters (proteins) encoded by 3 “bytes” (nucleotides) each. So you’re looking at O(10 billion) values of (i, b) that would still keep the string well-formed in its 3-bytes-per-character encoding.
Most importantly, it’s not saying anything about having some bytes b1 and b2 at the ith and jth positions or any generalization thereof.