27.2-27.3 S2. Parallel Recurrences (legacy compatibility path)
Third-edition-numbered compatibility path for this module. The canonical
fourth-edition source is
CLRSLean.FourthEdition.Chapter_26.Section_26_2_4_Algorithms.S2_Recurrences;
this module forwards to it so legacy imports keep working during the
compatibility period (see docs/migrations/clrs4.md).