@@ -14,16 +14,16 @@ public import Mathlib.Topology.Path
1414
1515This file defines H-spaces mainly following the approach proposed by Serre in his paper
1616*Homologie singulière des espaces fibrés* . The idea beneath `H-spaces` is that they are topological
17- spaces with a binary operation `⋀ : X → X → X` that is a homotopic -theoretic weakening of an
18- operation what would make `X` into a topological monoid.
19- In particular, there exists a "neutral element" `e : X` such that `fun x ↦e ⋀ x` and
17+ spaces with a binary operation `⋀ : X → X → X` that is a homotopy -theoretic weakening of an
18+ operation that would make `X` into a topological monoid.
19+ In particular, there exists a "neutral element" `e : X` such that `fun x ↦ e ⋀ x` and
2020`fun x ↦ x ⋀ e` are homotopic to the identity on `X`, see
2121[ the Wikipedia page of H-spaces ] (https://en.wikipedia.org/wiki/H-space).
2222
2323Some notable properties of `H-spaces` are
2424* Their fundamental group is always abelian (by the same argument for topological groups);
2525* Their cohomology ring comes equipped with a structure of a Hopf-algebra;
26- * The loop space based at every `x : X` carries a structure of an `H-spaces `.
26+ * The loop space based at every `x : X` carries a structure of an `H-space `.
2727
2828 ## Main Results
2929
@@ -32,14 +32,14 @@ Some notable properties of `H-spaces` are
3232* Given two `H-spaces` `X` and `Y`, their product is again an `H`-space. We show in an example that
3333 starting with two topological groups `G, G'`, the `H`-space structure on `G × G'` is
3434 definitionally equal to the product of `H-space` structures on `G` and `G'`.
35- * The loop space based at every `x : X` carries a structure of an `H-spaces `.
35+ * The loop space based at every `x : X` carries a structure of an `H-space `.
3636
3737 ## To Do
3838* Prove that for every `NormedAddTorsor Z` and every `z : Z`, the operation
3939 `fun x y ↦ midpoint x y` defines an `H-space` structure with `z` as a "neutral element".
4040* Prove that `S^0`, `S^1`, `S^3` and `S^7` are the unique spheres that are `H-spaces`, where the
4141 first three inherit the structure because they are topological groups (they are Lie groups,
42- actually), isomorphic to the invertible elements in `ℤ`, in `ℂ` and in the quaternion ; and the
42+ actually), isomorphic to the invertible elements in `ℤ`, in `ℂ` and in the quaternions ; and the
4343 fourth from the fact that `S^7` coincides with the octonions of norm 1 (it is not a group, in
4444 particular, only has an instance of `MulOneClass`).
4545
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