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TauCeti.Analysis.Analytic.Constructions

Slices of analytic functions of two variables #

Mathlib's AnalyticAt.curry_right says that a function analytic at p on a product has an analytic slice y โ†ฆ f (p.1, y) at p.2. Since the analytic locus is open, the same holds for the slices y โ†ฆ f (x, y) with x near p.1 (AnalyticAt.eventually_analyticAt_curry_right).

theorem AnalyticAt.eventually_analyticAt_curry_right {๐•œ : Type u_1} {E : Type u_2} {E' : Type u_3} {F : Type u_4} [NontriviallyNormedField ๐•œ] [NormedAddCommGroup E] [NormedSpace ๐•œ E] [NormedAddCommGroup E'] [NormedSpace ๐•œ E'] [NormedAddCommGroup F] [NormedSpace ๐•œ F] [CompleteSpace F] {f : E ร— E' โ†’ F} {p : E ร— E'} (hf : AnalyticAt ๐•œ f p) :
โˆ€แถ  (x : E) in nhds p.1, AnalyticAt ๐•œ (fun (y : E') => f (x, y)) p.2

The slices y โ†ฆ f (x, y) of a function analytic at p are analytic at p.2 for every x near p.1.