Algèbre et géométrie II Série 7

C⊂C− {i}C− {i}
X p, q ∈X α, β :I→X p q
X α β p q
α'pβ
A⊂X X r :X→A a0∈A
r∗:π1(X, a0)→π1(A, a0)
A B2={(x, y)∈R2|x2+y2≤1}f:A→A
f a ∈A f(a) = a
A= (aij )ij ∈M(3 ×3; R) det A6= 0 aij ≥0i, j A
(G, •)G(G, •)
•:G×G→G( )−1:G→G g 7→ g−1x0
G
Ω(G, x0)x0f, g ∈Ω(G, x0)fg∈Ω(G, x0)
(fg)(s) = f(s)•g(s).
(Ω(G, x0),)
π1(G, x0)
π1(G, x0)
π1(G, x0)