feat: port Analysis.Calculus.AffineMap (#4893)

Mathlib.lean

@@ -455,6 +455,7 @@ import Mathlib.Analysis.BoxIntegral.Partition.Measure
 import Mathlib.Analysis.BoxIntegral.Partition.Split
 import Mathlib.Analysis.BoxIntegral.Partition.SubboxInduction
 import Mathlib.Analysis.BoxIntegral.Partition.Tagged
+import Mathlib.Analysis.Calculus.AffineMap
 import Mathlib.Analysis.Calculus.BumpFunctionInner
 import Mathlib.Analysis.Calculus.Conformal.InnerProduct
 import Mathlib.Analysis.Calculus.Conformal.NormedSpace

Mathlib/Analysis/Calculus/AffineMap.lean

@@ -0,0 +1,42 @@
+/-
+Copyright (c) 2021 Oliver Nash. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+Authors: Oliver Nash
+
+! This file was ported from Lean 3 source module analysis.calculus.affine_map
+! leanprover-community/mathlib commit 839b92fedff9981cf3fe1c1f623e04b0d127f57c
+! Please do not edit these lines, except to modify the commit id
+! if you have ported upstream changes.
+-/
+import Mathlib.Analysis.NormedSpace.ContinuousAffineMap
+import Mathlib.Analysis.Calculus.ContDiff
+
+/-!
+# Smooth affine maps
+
+This file contains results about smoothness of affine maps.
+
+## Main definitions:
+
+ * `ContinuousAffineMap.contDiff`: a continuous affine map is smooth
+
+-/
+
+
+namespace ContinuousAffineMap
+
+variable {𝕜 V W : Type _} [NontriviallyNormedField 𝕜]
+
+variable [NormedAddCommGroup V] [NormedSpace 𝕜 V]
+
+variable [NormedAddCommGroup W] [NormedSpace 𝕜 W]
+
+/-- A continuous affine map between normed vector spaces is smooth. -/
+theorem contDiff {n : ℕ∞} (f : V →A[𝕜] W) : ContDiff 𝕜 n f := by
+  rw [f.decomp]
+  apply f.contLinear.contDiff.add
+  simp only
+  exact contDiff_const
+#align continuous_affine_map.cont_diff ContinuousAffineMap.contDiff
+
+end ContinuousAffineMap