Math 2.0

Real functions Proof

Proof of the implicit function theorem from the inverse function theorem

Builds on Inverse function theoremC^k function characterised by continuous derivativesJacobian matrixDeterminant of a block triangular matrixDeterminant of a transposeA matrix is invertible iff its determinant is a unitDerivative of the inverse function in several variablesContinuous partial derivatives imply differentiabilityChain rule in several variablesContinuity in R^n

Proof

We apply the inverse function theorem to the map Φ(x,y)=(x,F(x,y))\Phi(x, y) = (x, F(x, y)).

  1. Let Ω\Omega, FF and (a,b)(a, b) be as in the statement. Define Φ ⁣:Ω→ℝn×ℝm\Phi \colon \Omega \to \R^n \times \R^m by Φ(x,y)=(x,F(x,y))\Phi(x, y) = (x, F(x, y)).
  2. The components of Φ\Phi are the coordinates xix_i and the components of FF. So Φ\Phi is of class C^1, and its Jacobian matrix at (x,y)(x, y) is the block matrix (I0DxF(x,y)DyF(x,y))\begin{pmatrix} I & 0 \\ D_x F(x, y) & D_y F(x, y) \end{pmatrix}.
  3. By the determinant of a block triangular matrix, applied to the transpose, and since a matrix and its transpose have the same determinant, det⁡DΦ(x,y)=det⁡DyF(x,y)\det D\Phi(x, y) = \det D_y F(x, y).
  4. Since DyF(a,b)D_y F(a, b) is invertible, its determinant is not zero, so det⁡DΦ(a,b)≠0\det D\Phi(a, b) \ne 0.
  5. By the inverse function theorem with k=1k = 1, there are open sets V′⊆ΩV' \subseteq \Omega with (a,b)∈V′(a, b) \in V' and W′W' with Φ(a,b)=(a,0)∈W′\Phi(a, b) = (a, 0) \in W'. The map Φ\Phi is a bijection from V′V' onto W′W', with inverse Ψ ⁣:W′→V′\Psi \colon W' \to V' of class C1C^1.
  6. The map Φ\Phi does not change the first coordinate xx. So Ψ\Psi does not change it either: Ψ(x,z)=(x,η(x,z))\Psi(x, z) = (x, \eta(x, z)) for some η ⁣:W′→ℝm\eta \colon W' \to \R^m. The map η\eta is of class C1C^1, since its components are components of Ψ\Psi.
  7. For (x,z)∈W′(x, z) \in W', the equation Φ(Ψ(x,z))=(x,z)\Phi(\Psi(x, z)) = (x, z) says F(x,η(x,z))=zF(x, \eta(x, z)) = z.
  8. Since V′V' is open, there is r>0r > 0 such that every point within distance rr of (a,b)(a, b) lies in V′V'. Let U0={x:∥x−a∥<r/2}U_0 = \set{x : \norm{x - a} < r/2} and V={y:∥y−b∥<r/2}V = \set{y : \norm{y - b} < r/2}. If x∈U0x \in U_0 and y∈Vy \in V, then ∥(x,y)−(a,b)∥≤∥x−a∥+∥y−b∥<r\norm{(x, y) - (a, b)} \le \norm{x - a} + \norm{y - b} < r. So U0×V⊆V′U_0 \times V \subseteq V'.
  9. Let U={x∈U0:(x,0)∈W′ and η(x,0)∈V}U = \set{x \in U_0 : (x, 0) \in W' \text{ and } \eta(x, 0) \in V}. The map x↦(x,0)x \mapsto (x, 0) is continuous and W′W' is open, so the first condition defines an open set. On it, x↦η(x,0)x \mapsto \eta(x, 0) is continuous, and VV is open. So UU is open.
  10. We have Ψ(a,0)=(a,b)\Psi(a, 0) = (a, b), since Φ(a,b)=(a,0)\Phi(a, b) = (a, 0). So η(a,0)=b∈V\eta(a, 0) = b \in V, and a∈Ua \in U.
  11. Define g ⁣:U→Vg \colon U \to V by g(x)=η(x,0)g(x) = \eta(x, 0). By step 9, g(x)∈Vg(x) \in V. By step 7, F(x,g(x))=0F(x, g(x)) = 0 for x∈Ux \in U.
  12. Conversely, let (x,y)∈U×V(x, y) \in U \times V with F(x,y)=0F(x, y) = 0. Then (x,y)∈V′(x, y) \in V' by step 8, and Φ(x,y)=(x,0)=Φ(x,g(x))\Phi(x, y) = (x, 0) = \Phi(x, g(x)). Also (x,g(x))=Ψ(x,0)∈V′(x, g(x)) = \Psi(x, 0) \in V'.
  13. Since Φ\Phi is injective on V′V', we get y=g(x)y = g(x). With step 11: for (x,y)∈U×V(x, y) \in U \times V, F(x,y)=0F(x, y) = 0 if and only if y=g(x)y = g(x).
  14. The function gg is unique. If g~ ⁣:U→V\tilde g \colon U \to V has the same property, then F(x,g~(x))=0F(x, \tilde g(x)) = 0 with (x,g~(x))∈U×V(x, \tilde g(x)) \in U \times V, so g~(x)=g(x)\tilde g(x) = g(x) by step 13.
  15. The function gg is the composition of x↦(x,0)x \mapsto (x, 0) with the C1C^1 map η\eta. By the chain rule, ∂g/∂xi(x)=∂η/∂xi(x,0)\partial g / \partial x_i (x) = \partial \eta / \partial x_i (x, 0), which is continuous. So gg is of class C1C^1.
  16. Let x∈Ux \in U. The maps Φ\Phi and Ψ\Psi are differentiable, by continuous partials. By the derivative of the inverse function, DΦ(x,g(x))D\Phi(x, g(x)) is invertible. By step 3 and the determinant criterion, DyF(x,g(x))D_y F(x, g(x)) is invertible.
  17. Differentiate the identity F(x,g(x))=0F(x, g(x)) = 0 on the open set UU with the chain rule. This gives DxF(x,g(x))+DyF(x,g(x)) Dg(x)=0D_x F(x, g(x)) + D_y F(x, g(x)) \, Dg(x) = 0.
  18. Multiplying on the left by (DyF(x,g(x)))−1\big( D_y F(x, g(x)) \big)^{-1} gives Dg(x)=−(DyF(x,g(x)))−1DxF(x,g(x))Dg(x) = -\big( D_y F(x, g(x)) \big)^{-1} D_x F(x, g(x)).

Idea

The map (x,y)↦(x,F(x,y))(x, y) \mapsto (x, F(x, y)) keeps xx and records the value of FF. Its derivative is invertible exactly when DyFD_y F is, so it has a local inverse. Reading off the inverse at the points (x,0)(x, 0) gives the solution y=g(x)y = g(x) of F(x,y)=0F(x, y) = 0, and differentiating F(x,g(x))=0F(x, g(x)) = 0 gives the formula for DgDg.

Reading path

To understand this page from the ground up, read these 448 pages in order. The foundations come first. The path takes the proofs Proof of the limit of a sum of sequences, Proof of Rolle's theorem, Proof of the derivative of a map into R^n by components, Proof of the approximation property of the supremum, Proof that every sequence has a monotone subsequence, by peaks, Proof of the decomposition of a permutation into transpositions, Proof that the symmetric group is generated by transpositions, Proof of the Laplace expansion along a column by transposition, Proof that open sets are the sets that are neighbourhoods of all their points, Proof that closed balls are closed, Proof of the diameter characterisation of Cauchy sequences, Proof of the commutativity of addition by induction, Proof of the Lebesgue number lemma by a finite cover of balls, Proof of the epsilon-delta form of continuity, Proof that equivalence classes form a partition, Proof of the triangle inequality for norms, Proof of the sum of a finite geometric series, Proof that a complex number times its conjugate is the square of its modulus, Proof of the Cauchy–Schwarz inequality, Proof of the Heine–Borel theorem by sequential compactness, Proof that there is a natural number n with 1/n below any positive epsilon, Proof of the chain rule in several variables, Proof that the determinant is multiplicative by expanding the rows, Proof that permuting rows multiplies the determinant by the sign, Proof that closed subsets of complete spaces are complete, Proof of the derivative as a little-o approximation, Proof that disjoint cycles commute, Proof of the equality of complex numbers, Proof that a matrix is invertible iff its determinant is a unit, Proof that a linear map between normed spaces is continuous if and only if it is bounded, Proof of the determinant of a block triangular matrix by the Leibniz formula, Proof that a function is bijective iff it has a two-sided inverse, Proof that the reals form an ordered field, with the Cauchy sequence construction, Proof of continuity via closed sets, Proof that a matrix with two equal rows has determinant zero, Proof of the double negation law by a truth table, Proof of the extreme value theorem by the Bolzano–Weierstrass theorem, Proof that compact subsets of a metric space are bounded, Proof of the Laplace expansion along a row by the Leibniz formula, Proof that compactness and sequential compactness agree in metric spaces, Proof that subsequences of a convergent sequence converge to the same limit, Proof of the uniqueness of limits, Proof that the coordinate map is a linear isomorphism, Proof of strong induction from ordinary induction, Proof that linear maps on finite-dimensional normed spaces are continuous, Proof that the determinant of a transpose equals the determinant, Proof of the laws of exponents in a group, Proof of the limit of a product of sequences, Proof of the inverse in terms of the adjugate, Proof that the absolute value is multiplicative, Proof of the squeeze theorem for sequences, Proof of the existence of square roots of nonnegative reals, Proof of the chain rule for a composition with a curve, Proof of the linearity of differentiation, Proof that a continuous image of a compact set is compact, Proof that compact subsets of a Hausdorff space are closed, Proof that the composition of continuous maps is continuous, Proof of epsilon-delta continuity at a point in metric spaces, Proof of the sequential characterization of limits, Proof of the description of the open sets of a metric space, Proof of the Banach fixed point theorem by iteration, Proof of the triangle inequality for real numbers, Proof that an intersection of subgroups is a subgroup, Proof of the epsilon-N definition of the limit of a sequence, Proof that compactness of a subset can be tested with open sets of the ambient space, Proof that the sign is a homomorphism, Proof of the existence of the infimum by negation, Proof of the equivalence of norms in finite dimension by compactness of the unit sphere, Proof of the determinant of the inverse, Proof that every spanning set contains a basis, by Zorn's lemma, Proof that the determinant of the identity matrix is one, Proof of Fermat's theorem on stationary points, Proof that limits preserve non-strict inequalities, Proof of the inverse function theorem by the contraction mapping principle, Proof that closed sets contain their limits, Proof of Zorn's lemma, Proof that metric spaces are Hausdorff, Proof that the derivative gives the directional derivatives, Proof that differentiable functions are continuous, Proof of the decomposition of a permutation into disjoint cycles, Proof of the product of a matrix and its adjugate by Laplace expansion, Proof of the sequence characterisation of uniform continuity, Proof of the epsilon-delta form of the limit of a function, Proof of the well-ordering principle from strong induction, Proof of the Bolzano–Weierstrass theorem by a monotone subsequence, Proof of the division algorithm, Proof of the Archimedean property in an Archimedean ordered field, Proof of the sign of a cycle, Proof that finite-dimensional normed spaces are complete, Proof that a continuous real function on a compact set attains its bounds, Proof of the Leibniz formula from the defining properties of the determinant, Proof of the uniqueness of inverses, Proof of the derivative of a map into a product, Proof that a decreasing sequence bounded below converges, Proof that the reals are Archimedean from the completeness axiom, Proof that convergent sequences are bounded, Proof of the monotone convergence theorem for sequences, Proof that continuity is equivalent to sequential continuity, Proof that the determinant is multilinear in the rows, Proof that open balls are open, Proof of the boundedness theorem by Bolzano–Weierstrass, Proof that Lipschitz maps are uniformly continuous, Proof that C^k functions are characterised by continuous derivatives, Proof that continuous partial derivatives imply differentiability, Proof that a set is open if and only if its complement is closed, Proof of the subgroup criterion, Proof of the mean value theorem from Rolle's theorem, Proof of continuity via open sets in metric spaces, Proof of the mean value inequality, Proof of the constant multiple rule.

  1. Affine combination concept
  2. Basis concept
  3. Binary operation definition
  4. Complex numbers object
  5. Complex numbers as pairs of reals concept
  6. Construction of the reals from Cauchy sequences concept
  7. Coordinate space object
  8. Coordinate vector concept
  9. Cycle notation concept
  10. Definition by recursion concept
  11. Divisibility definition
  12. Element definition
  13. Euclidean metric example
  14. Euclidean space object
  15. Extended real number line object
  16. Function concept
  17. Function composition concept
  18. Group concept
  19. Identity matrix object
  20. Imaginary unit object
  21. Inner product concept
  22. Inner product space concept
  23. Integers object
  24. Limit point of a set definition
  25. Linear isomorphism concept
  26. Linear map concept
  27. Local maximum definition
  28. Mathematical induction concept
  29. Matrix definition
  30. Multilinear map concept
  31. Natural numbers object
  32. Norm concept
  33. Norm induced by an inner product concept
  34. Ordered field definition
  35. Peano axioms concept
  36. Permutation concept
  37. Permutation definition
  38. Proof of Zorn's lemma proof
  39. Proposition concept
  40. Rational numbers object
  41. Real numbers object
  42. Sequence definition
  43. Set bounded above definition
  44. Transposition concept
  45. Vector space definition
  46. p-metric on R^n example
  47. Identity element definition
  48. Real and imaginary parts definition
  49. Convex set definition
  50. Set definition
  51. Fréchet derivative definition
  52. Having a directional derivative definition
  53. Total derivative concept
  54. Function of several variables concept
  55. Vector-valued function concept
  56. Group homomorphism definition
  57. Ring definition
  58. Subgroup definition
  59. Symmetric group definition
  60. Ring of integers statement
  61. Limit of a function definition
  62. Local minimum definition
  63. Block matrix definition
  64. Matrix multiplication definition
  65. Square matrix definition
  66. Transpose definition
  67. Successor function definition
  68. Archimedean ordered field definition
  69. Conjunction definition
  70. Disjunction definition
  71. Implication definition
  72. Negation definition
  73. Predicate definition
  74. The reals form a field statement
  75. Real sequence definition
  76. Subsequence definition
  77. Infimum definition
  78. Supremum definition
  79. Inner product definition
  80. Linear combination definition
  81. Linear map definition
  82. Linear subspace definition
  83. Norm definition
  84. p-norm on R^n example
  85. Inverse element definition
  86. Complex conjugate definition
  87. Empty set object
  88. Family of sets definition
  89. Ordered pair definition
  90. Differentiable function of several variables concept
  91. Partial derivative concept
  92. Limit of a function of several variables concept
  93. Transposition definition
  94. Unit of a ring definition
  95. Parametrised curve concept
  96. Intersection definition
  97. Union definition
  98. Continuity at a point definition
  99. Derivative definition
  100. Proof that an intersection of subgroups is a subgroup proof
  101. Set-builder notation concept
  102. Invertible matrix definition
  103. Addition of natural numbers definition
  104. Biconditional definition
  105. Truth table concept
  106. Modus ponens concept
  107. Existential quantifier definition
  108. The rationals form a field statement
  109. Universal quantifier definition
  110. Proof of the Archimedean property in an Archimedean ordered field proof
  111. The successor function is injective statement
  112. Zero is not a successor statement
  113. Bounded sequence definition
  114. Cauchy sequence definition
  115. Geometric sequence definition
  116. Limit of a sequence definition
  117. Monotone sequence definition
  118. Inner product space definition
  119. Linear independence definition
  120. Composition of linear maps definition
  121. Linear isomorphism definition
  122. Linear span definition
  123. Multilinear map definition
  124. Normed vector space definition
  125. Completeness axiom statement
  126. Cartesian product definition
  127. Gradient concept
  128. Jacobian matrix concept
  129. Proof of the equality of complex numbers proof
  130. Disjoint sets definition
  131. Proof of the uniqueness of inverses proof
  132. Partial derivative definition
  133. Continuity in R^n definition
  134. Differentiable function of several variables definition
  135. Union of a family of sets definition
  136. Continuous function definition
  137. Differentiable function definition
  138. Axiom of extensionality statement
  139. Subset definition
  140. Mathematical proof concept
  141. Proof of the derivative as a little-o approximation proof
  142. Proof of the commutativity of addition by induction proof
  143. Archimedean property statement
  144. Uniqueness quantifier definition
  145. Order on the natural numbers definition
  146. Propositional logic concept
  147. The rationals form an ordered field statement
  148. Proof of the sum of a finite geometric series proof
  149. Convergent sequence definition
  150. Sequential continuity definition
  151. Norm induced by an inner product definition
  152. Spanning set definition
  153. Alternating multilinear map definition
  154. Equality of complex numbers statement
  155. Higher partial derivatives definition
  156. Binary relation definition
  157. Jacobian matrix definition
  158. Uniqueness of inverses statement
  159. Differentiable on an open set definition
  160. Universal set definition
  161. Partition of a set definition
  162. Topological space definition
  163. Derivative as a little-o approximation statement
  164. Proof of the derivative of a map into R^n by components proof
  165. Order on the reals definition
  166. Tautology definition
  167. Commutativity of addition statement
  168. Determinant definition
  169. Proof of strong induction from ordinary induction proof
  170. Finite-dimensional vector space definition
  171. Sum of a finite geometric series statement
  172. Basis definition
  173. Antisymmetric relation definition
  174. Reflexive relation definition
  175. Symmetric relation definition
  176. Transitive relation definition
  177. Jacobian determinant definition
  178. Iterated derivative definition
  179. Sequential compactness definition
  180. Complement definition
  181. Function definition
  182. Proof of the laws of exponents in a group proof
  183. Proof of the subgroup criterion proof
  184. Subspace topology definition
  185. Interval definition
  186. Proof that a matrix with two equal rows has determinant zero proof
  187. Proof that the determinant of the identity matrix is one proof
  188. Logical equivalence definition
  189. Coordinate vector definition
  190. Strong induction statement
  191. Minor definition
  192. Proof that the determinant is multilinear in the rows proof
  193. Equivalence relation definition
  194. Preorder definition
  195. Codomain definition
  196. Function composition definition
  197. Identity function definition
  198. Injective function definition
  199. Choice function definition
  200. Image of a set definition
  201. Preimage of a set definition
  202. Restriction of a function definition
  203. Subgroup criterion statement
  204. Proof of the epsilon-delta form of continuity proof
  205. Laws of exponents in a group statement
  206. Proof of the epsilon-delta form of the limit of a function proof
  207. Determinant of a matrix with two equal rows statement
  208. Determinant of the identity matrix statement
  209. Metric space definition
  210. Determinant is multilinear in the rows statement
  211. Cofactor definition
  212. Proof of the well-ordering principle from strong induction proof
  213. Proof of the double negation law by a truth table proof
  214. Partial order definition
  215. Left inverse definition
  216. Right inverse definition
  217. Surjective function definition
  218. Axiom of choice statement
  219. Proof that disjoint cycles commute proof
  220. Equivalence class definition
  221. Epsilon-delta definition of continuity statement
  222. Intersection of subgroups is a subgroup statement
  223. Subspace metric definition
  224. Epsilon-delta definition of a limit statement
  225. Closed ball definition
  226. Convergence of a sequence in a metric space definition
  227. Lipschitz map definition
  228. Open ball definition
  229. Triangle inequality for a metric statement
  230. Adjugate matrix definition
  231. Double negation law statement
  232. Diameter of a set definition
  233. Well-ordering principle statement
  234. Maximal element definition
  235. Total order definition
  236. Upper bound definition
  237. Bijective function definition
  238. Proof that equivalence classes form a partition proof
  239. Disjoint cycles commute statement
  240. Subgroup generated by a subset definition
  241. Metric topology definition
  242. Bounded set definition
  243. Contraction mapping definition
  244. Proof by contradiction concept
  245. Proof of the division algorithm proof
  246. Proof of the diameter characterisation of Cauchy sequences proof
  247. Proof that every sequence has a monotone subsequence, by peaks proof
  248. Chain definition
  249. Proof that a function is bijective iff it has a two-sided inverse proof
  250. Equivalence classes form a partition statement
  251. Open set definition
  252. Division algorithm statement
  253. Epsilon characterisation of Cauchy sequences statement
  254. Proof that the reals form an ordered field, with the Cauchy sequence construction proof
  255. Every sequence has a monotone subsequence statement
  256. Bijective iff it has a two-sided inverse statement
  257. Hausdorff space definition
  258. Closed set definition
  259. Open cover definition
  260. Continuous map of topological spaces definition
  261. Proof that open sets are the sets that are neighbourhoods of all their points proof
  262. Proof of the decomposition of a permutation into disjoint cycles proof
  263. Proof that the derivative gives the directional derivatives proof
  264. Zorn's lemma statement
  265. Equivalent metrics definition
  266. Proof of the description of the open sets of a metric space proof
  267. Complete metric space definition
  268. The reals form an ordered field statement
  269. Compact space definition
  270. Proof that a set is open if and only if its complement is closed proof
  271. Proof that the composition of continuous maps is continuous proof
  272. Open sets characterised by neighbourhoods statement
  273. Derivative gives the directional derivatives statement
  274. Decomposition of a permutation into disjoint cycles statement
  275. Equivalent norms definition
  276. Open sets of a metric space statement
  277. Proof that the coordinate map is a linear isomorphism proof
  278. Absolute value definition
  279. Proof that every spanning set contains a basis, by Zorn's lemma proof
  280. Proof of the approximation property of the supremum proof
  281. Proof of the existence of the infimum by negation proof
  282. Proof of the existence of square roots of nonnegative reals proof
  283. Complement of an open set is closed statement
  284. Composition of continuous maps is continuous statement
  285. Continuous linear map definition
  286. Compact set definition
  287. Continuity at a point of a topological space definition
  288. Proof of the decomposition of a permutation into transpositions proof
  289. Banach space definition
  290. Proof that closed sets contain their limits proof
  291. Proof of the triangle inequality for real numbers proof
  292. Proof that the absolute value is multiplicative proof
  293. Proof that closed balls are closed proof
  294. Proof that open balls are open proof
  295. Every spanning set contains a basis statement
  296. Isomorphism with the coordinate space statement
  297. Proof of the epsilon-N definition of the limit of a sequence proof
  298. Existence of square roots of nonnegative reals statement
  299. Approximation property of the supremum statement
  300. Existence of the infimum statement
  301. Proof that compactness of a subset can be tested with open sets of the ambient space proof
  302. Proof of continuity via closed sets proof
  303. Decomposition of a permutation into transpositions statement
  304. Closed sets contain their limits statement
  305. Triangle inequality statement
  306. Absolute value is multiplicative statement
  307. Closed balls are closed statement
  308. Open balls are open statement
  309. Square root definition
  310. Epsilon-N definition of the limit of a sequence statement
  311. Proof that the reals are Archimedean from the completeness axiom proof
  312. Sign of a permutation definition
  313. Continuity via closed sets statement
  314. Modulus of a complex number definition
  315. Compactness via open covers statement
  316. Proof of the limit of a sum of sequences proof
  317. Proof that closed subsets of complete spaces are complete proof
  318. Proof of the uniqueness of limits proof
  319. Proof that the symmetric group is generated by transpositions proof
  320. Proof of epsilon-delta continuity at a point in metric spaces proof
  321. Proof of the squeeze theorem for sequences proof
  322. Proof of the Lebesgue number lemma by a finite cover of balls proof
  323. Proof of continuity via open sets in metric spaces proof
  324. Proof that limits preserve non-strict inequalities proof
  325. Proof that differentiable functions are continuous proof
  326. Proof that metric spaces are Hausdorff proof
  327. Proof that convergent sequences are bounded proof
  328. The reals are Archimedean statement
  329. Proof that subsequences of a convergent sequence converge to the same limit proof
  330. Proof of the monotone convergence theorem for sequences proof
  331. Proof that compact subsets of a Hausdorff space are closed proof
  332. Proof that a complex number times its conjugate is the square of its modulus proof
  333. Proof that a continuous image of a compact set is compact proof
  334. The symmetric group is generated by transpositions statement
  335. Proof that the sign is a homomorphism proof
  336. Closed subsets of complete spaces are complete statement
  337. Proof of the sign of a cycle proof
  338. Lebesgue number lemma statement
  339. Epsilon-delta continuity in metric spaces statement
  340. Proof that compact subsets of a metric space are bounded proof
  341. Metric spaces are Hausdorff statement
  342. Proof that compactness and sequential compactness agree in metric spaces proof
  343. Differentiable functions are continuous statement
  344. Limit of a sum of sequences statement
  345. Proof of the sequence characterisation of uniform continuity proof
  346. Uniqueness of limits statement
  347. Proof of the triangle inequality for norms proof
  348. Limits preserve non-strict inequalities statement
  349. Convergent sequences are bounded statement
  350. Squeeze theorem statement
  351. Proof that there is a natural number n with 1/n below any positive epsilon proof
  352. Subsequences of a convergent sequence converge to the same limit statement
  353. Monotone convergence theorem for sequences statement
  354. A complex number times its conjugate statement
  355. Compact subsets of a Hausdorff space are closed statement
  356. Sign of a cycle statement
  357. Continuous image of a compact set is compact statement
  358. Sign is a homomorphism statement
  359. Compactness and sequential compactness agree in metric spaces statement
  360. Continuity via open sets statement
  361. Compact subsets of a metric space are bounded statement
  362. Proof of the limit of a product of sequences proof
  363. Epsilon-delta uniform continuity statement
  364. Proof that permuting rows multiplies the determinant by the sign proof
  365. There is a natural number n with 1/n below any positive epsilon statement
  366. Proof that a decreasing sequence bounded below converges proof
  367. Triangle inequality for norms statement
  368. The sequence r^n tends to zero for |r| < 1 example
  369. Proof that a linear map between normed spaces is continuous if and only if it is bounded proof
  370. Permuting rows multiplies the determinant by the sign statement
  371. Proof of the Banach fixed point theorem by iteration proof
  372. Proof that Lipschitz maps are uniformly continuous proof
  373. Proof of the sequential characterization of limits proof
  374. Proof that continuity is equivalent to sequential continuity proof
  375. Proof of the Cauchy–Schwarz inequality proof
  376. Decreasing sequence bounded below converges statement
  377. Limit of a product of sequences statement
  378. Banach fixed point theorem statement
  379. Lipschitz maps are uniformly continuous statement
  380. Continuity is equivalent to sequential continuity statement
  381. Proof of the Leibniz formula from the defining properties of the determinant proof
  382. Sequential characterization of limits statement
  383. Proof of the Bolzano–Weierstrass theorem by a monotone subsequence proof
  384. Cauchy–Schwarz inequality statement
  385. Bounded linear maps are continuous statement
  386. Leibniz formula for determinants statement
  387. Proof of the linearity of differentiation proof
  388. Bolzano–Weierstrass theorem statement
  389. Proof of the derivative of a map into a product proof
  390. Proof of the determinant of a block triangular matrix by the Leibniz formula proof
  391. Linearity of differentiation statement
  392. Proof of the Heine–Borel theorem by sequential compactness proof
  393. Operator norm definition
  394. Proof of the Laplace expansion along a row by the Leibniz formula proof
  395. Proof that the determinant is multiplicative by expanding the rows proof
  396. Proof that the determinant of a transpose equals the determinant proof
  397. Proof of the boundedness theorem by Bolzano–Weierstrass proof
  398. Completeness of the real numbers statement
  399. Derivative of a map into a product statement
  400. Proof of the constant multiple rule proof
  401. Heine–Borel theorem statement
  402. Boundedness theorem statement
  403. Determinant of a block triangular matrix statement
  404. Determinant is multiplicative statement
  405. Laplace expansion along a row statement
  406. Determinant of a transpose statement
  407. Constant multiple rule statement
  408. Derivative of a map into R^n by components statement
  409. Proof of the determinant of the inverse proof
  410. Proof of the Laplace expansion along a column by transposition proof
  411. Proof of the extreme value theorem by the Bolzano–Weierstrass theorem proof
  412. Proof that a continuous real function on a compact set attains its bounds proof
  413. Extreme value theorem statement
  414. Determinant of the inverse statement
  415. Continuous real function on a compact set attains its bounds statement
  416. Laplace expansion along a column statement
  417. Proof of Fermat's theorem on stationary points proof
  418. Proof of the equivalence of norms in finite dimension by compactness of the unit sphere proof
  419. Proof of the product of a matrix and its adjugate by Laplace expansion proof
  420. Fermat's theorem on stationary points statement
  421. Equivalence of norms in finite dimension statement
  422. Product of a matrix and its adjugate statement
  423. Proof of Rolle's theorem proof
  424. Rolle's theorem statement
  425. Proof that linear maps on finite-dimensional normed spaces are continuous proof
  426. Proof that finite-dimensional normed spaces are complete proof
  427. Proof of the inverse in terms of the adjugate proof
  428. Linear maps on finite-dimensional spaces are continuous statement
  429. Finite-dimensional normed spaces are complete statement
  430. Proof of the mean value theorem from Rolle's theorem proof
  431. Inverse in terms of the adjugate statement
  432. Mean value theorem statement
  433. Proof that a matrix is invertible iff its determinant is a unit proof
  434. Proof of the chain rule in several variables proof
  435. Proof that continuous partial derivatives imply differentiability proof
  436. Chain rule in several variables statement
  437. A matrix is invertible iff its determinant is a unit statement
  438. Derivative of the inverse function in several variables statement
  439. Continuous partial derivatives imply differentiability statement
  440. Proof of the chain rule for a composition with a curve proof
  441. Chain rule for a composition with a curve statement
  442. Proof that C^k functions are characterised by continuous derivatives proof
  443. C^k function characterised by continuous derivatives statement
  444. Proof of the mean value inequality proof
  445. Mean value inequality statement
  446. Proof of the inverse function theorem by the contraction mapping principle proof
  447. Inverse function theorem statement
  448. Proof of the implicit function theorem from the inverse function theorem proof

Where this leads

22 pages build on this one.

Further reading

  1. Web https://en.wikipedia.org/wiki/Inverse_function_theorem, Implicit function theorem
About this page
Tag35SNAG4VF8
URIm2://35SNAG4VF8
Kindproof
WritingW0 stub
MSC26B10
ProvesImplicit function theorem
UsesInverse function theorem, C^k function characterised by continuous derivatives, Jacobian matrix, Determinant of a block triangular matrix, Determinant of a transpose, A matrix is invertible iff its determinant is a unit, Derivative of the inverse function in several variables, Continuous partial derivatives imply differentiability, Chain rule in several variables, Continuity in R^n
Changed4 November 2026

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