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The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
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These labels describe origin, not correctness: citations and verification chips remain separate evidence.
Transverse complementary submanifolds meet in finitely many points
Statement
Let be a Hausdorff smooth -manifold and let be compact embedded smooth submanifolds without boundary, of dimensions and . Assume they are transverse, meaning for every . Then is finite.
Statement references
Facts & Assumptions
Given: The Hausdorff smooth manifold and the compact embedded submanifolds in the statement.
Embedded smooth submanifolds with boundary only requires the inclusion to be a smooth embedding. The published slice-chart theorem Boundary submanifolds of a boundaryless manifold have half-slice charts supplies the missing local form: because has no boundary, every is an interior point of its manifold-with-boundary structure, so near it is an ordinary coordinate slice.
The smooth inverse function theorem on manifolds states that a smooth map with invertible differential at a point restricts to a diffeomorphism between neighborhoods of that point and its image.
In a Hausdorff space a point and a disjoint compact set, and two disjoint compact sets, have disjoint open neighbourhoods; hence every compact subset is closed, and in a compact Hausdorff space the compact subsets are exactly the closed ones states that compact subsets of a Hausdorff space are closed.
Proof
Given: Put . At every intersection point, the hypothesis is .
Since is compact and is Hausdorff, [F3] makes closed in . Thus is closed in the compact space , hence compact.
Fix . By [F1], choose coordinates near with given by . The coordinate projection restricted to has derivative with kernel , because the two tangent dimensions sum to and their sum is . Its domain and target both have dimension , so this derivative is an isomorphism. By [F2], after shrinking a neighborhood of in , the map is one-to-one. The only point of that neighborhood lying in is therefore ; hence is isolated in .
Every point of is isolated by step 1.2, so its singleton neighborhoods form an open cover of the compact subspace . Compactness gives a finite subcover, which means is finite. If , the conclusion holds directly.
Statement references
Depends on
Smooth manifolds and their smooth charts
Embedded smooth submanifolds with boundary
Boundary submanifolds of a boundaryless manifold have half-slice charts
The smooth inverse function theorem on manifolds
In a Hausdorff space a point and a disjoint compact set, and two disjoint compact sets, have disjoint open neighbourhoods; hence every compact subset is closed, and in a compact Hausdorff space the compact subsets are exactly the closed ones