An exploration of functional logarithms and exponentials for formal power series, enabling computation of fractional iterates of functions (e.g., the 'square root' of sin). The approach avoids the naive power-series-of-power-series method (which fails due to lack of distributivity) by using a clever operator that restores right-distributivity. The resulting `flog` and `fexp` functions are implemented in idiomatic lazy-list-based lazy evaluation in haskell, verified against known sequences in the oeis, and connected to differential geometry via flows and exponential maps.
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