= Coding of real sequences by ternary digits
{title2=$c(s)=\sum_{n,k\geq1}a_{nk}3^{-j(n,k)}$}
Map each real into $(0,1)$, choose its canonical <binary expansion>, and flatten the resulting countable array of bits using a <bijection> $j:\mathbb N^2\to\mathbb N$. Interpret these bits as ternary digits zero and one. At a first differing position, the leading difference exceeds the sum of all possible tail differences, so this is an <injection> from real sequences to a bounded real interval. The bijection $j(n,k)=(n+k-2)(n+k-1)/2+n$ lists successive finite diagonals.
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