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Calvin Khor
Calvin Khor
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I'm done replacing the links in the planetmath-failures list provided by Glorfindel.

Methodology: It seems the errors were because the URL were changed to match the title. Given this, all I had to do was find the posts on the Wayback Machine and find the title in the index. There were also some other non-Planetmath links; all but two (#1, #2) were fixed; some comments were left on the exceptions.

Notably I found some links that were not in the list. These seem to be links that were 'bare', i.e. without any markdown or HTML formatting to include them as hyperlinks.

Here is my spreadsheet (I will remove this in the next edit to save on screen real-estate, then link to the first revision)

Frequency URL Links Replacement / comments
2 http://planetmath.org/encyclopedia/ABanachSpaceOfInfiniteDimensionDoesntHaveACountableAlgebraicBasis.html Let $X$ be an infinite dimensional Banach space. Prove that every Hamel basis of $X$ is uncountable. ; https://math.stackexchange.com/a/136818/80734 https://planetmath.org/banachspacesofinfinitedimensiondonothaveacountablehamelbasis
2 http://planetmath.org/encyclopedia/DifferentiationUnderIntegralSign.html How to solve combinations of differentials and integrals? ; Computing Some Integrals via Gauss Integral https://planetmath.org/differentiationundertheintegralsign
2 http://planetmath.org/encyclopedia/Folded.html Verify this distribution convolution: $E(t,x)\ast (g(x)\delta(t)) = t\int_{\omega\in S^2}{\frac{g(x-t\omega)}{4\pi}dS(\omega)}$ ; Are there any interesting semigroups that aren't monoids? https://planetmath.org/convolution
2?found3 http://planetmath.org/encyclopedia/ProofThatAllNormsOnFiniteVectorSpaceAreEquivalent.html How to prove $C_1 \|x\|_\infty \leq \|x\| \leq C_2 \|x\|_\infty$? What is the difference between the operator norm and the Euclidean norm? ; Point-wise and Norm Convergence of Vectors in a finite dimensional space https://planetmath.org/allnormsonfinitedimensionalvectorspacesareequivalent
1 http://bib.tiera.ru/ShiZ/math/other/Basic%20Analysis%20-%20K.%20Kuttler.pdf https://math.stackexchange.com/a/86671/80734 replaced with ZBMath link https://zbmath.org/?q=an%3A1034.26001; as the PDF may be illegal to share (but the PDF is easy to google if you care)
but diagram is missing1 http://noosphere.planetmath.org/encyclopedia/HartogsTriangle.html Complex 3-D Euclidean space - inner product https://planetmath.org/hartogstriangle
1 http://planetmath.org/encyclopedia/AssociativityOfConvolution.html Convolution on group with measure https://planetmath.org/convolutionassociativityof
1 http://planetmath.org/encyclopedia/CauchySequence2.html Definition of a Cauchy sequence in terms of a Cauchy filter https://planetmath.org/completeuniformspace
1 http://planetmath.org/encyclopedia/ClosedOpen.html How to define a bijection between $(0,1)$ and $(0,1]$? https://planetmath.org/openandclosedintervalshavethesamecardinality
1?found2 http://planetmath.org/encyclopedia/CompactMetricSpacesAreSecondCountable.html Why is any compact metric space the union of a countable set a subset which is a perfect space under the induced topology? ; In this proof that a compact metric space is second countable, why exactly is the induced topology the same as the metric topology? https://planetmath.org/acompactmetricspaceissecondcountable
1?Found2 http://planetmath.org/encyclopedia/CondensationPoints.html Counterexamples about set of condensation points in metric spaces ; https://math.stackexchange.com/a/96570/80734 https://planetmath.org/condensationpoint (but only left a comment on Is there a name encompassing both limit inferior and limit superior)
1 http://planetmath.org/encyclopedia/FirstCategory.html Definitions of Baire first and second category sets https://planetmath.org/meager
1 http://planetmath.org/encyclopedia/FourierStieltjesAndMeasuredGroupoidTransforms.html minus sign in the exponent of kernels of integral transformations https://planetmath.org/tableofgeneralizedfourierandmeasuredgroupoidtransforms
1 http://planetmath.org/encyclopedia/GaloisGroupOfTheCubic.html Galois Theory and Number of Solutions https://planetmath.org/galoisgroupofacubicpolynomial
1 http://planetmath.org/encyclopedia/HalfGCDAlgorithm.html Quick way to find the highest multiplicity of a divisor of a number? https://planetmath.org/fasteuclideanalgorithm
1 http://planetmath.org/encyclopedia/HallWittIdentity.html commutator identity on planetmath https://planetmath.org/propertiesofgroupcommutatorsandcommutatorsubgroups
1 http://planetmath.org/encyclopedia/IrreducibleSet.html The product of two spectral spaces https://planetmath.org/soberspace
1 http://planetmath.org/encyclopedia/LaplaceTransformOfSincFunction.html Integrating $\int\nolimits_0^{\infty}{\frac{e^{-ax}-e^{-bx}}{x}\sin{mx} \, dx} \quad (a > 0 \, , b >0)$ https://planetmath.org/laplacetransformofsineintegral
1 http://planetmath.org/encyclopedia/LeftDerivative.html Norm with special conditions probably http://planetmath.org/onesidedderivatives
1 http://planetmath.org/encyclopedia/MathcalFMeasurableFunction.html Random variable on Lebesgue measure maybe http://planetmath.org/measurablefunction
1 http://planetmath.org/encyclopedia/MazursTheorem.html Property of elliptic curves with a torsion point https://planetmath.org/mazurstheoremontorsionofellipticcurves
1 http://planetmath.org/encyclopedia/OrthogonalComplement.html Complementary Subspaces https://planetmath.org/complementarysubspace
1 http://planetmath.org/encyclopedia/PappussTheoremForSurfacesOfRevolution.html Symmetry of Solution to Classical 3-Dimensional Isoperimetric Problem https://planetmath.org/pappusscentroidtheorem
1 http://planetmath.org/encyclopedia/ProjectiveGeometry3.html orthogonal polarity and bilinear form https://planetmath.org/projectivegeometry
1 http://planetmath.org/encyclopedia/PruferPGroup.html Is this true? Every abelian $p$-group is isomorphic to some direct sum of cyclic $p$-groups. https://planetmath.org/quasicyclicgroup
1 http://planetmath.org/encyclopedia/QuadraticField.html Is this a known algebraic identity: $ (a + P \sqrt{t})^n \times (a - P \sqrt{t})^n = 1 $? http://planetmath.org/numberfield
1 http://planetmath.org/encyclopedia/QuasiHamiltonianGroup.html Cancellation of Direct Products https://planetmath.org/hamiltoniangroup; also fixed a different answer https://math.stackexchange.com/posts/2196/revisions from http://planetmath.org/encyclopedia/KrullRemakSchmidtTheorem.html to https://planetmath.org/krullschmidttheorem
1 http://planetmath.org/encyclopedia/SawBladeFunction.html Describing a Wave ??? but the answer doesn’t look great so I am OK to not edit. Old wayback sort of works: https://web.archive.org/web/20080328064146/http://planetmath.org/encyclopedia/SawBladeFunction.html ; another consideration is https://planetmath.org/commonfourierseries (which itself has a broken link to http://planetmath.org/triangularwavefunction)
1 http://planetmath.org/encyclopedia/TaylorPolynomialsInBanachSpaces.html a property of log determinant https://planetmath.org/taylorsformulainbanachspaces
1 http://planetmath.org/encyclopedia/UniversalTrigonometricSubstitution.html Summing the power series $\sum\limits_{n=0}^\infty (-1)^n \frac{x^{2n+1}}{2n+1}\prod\limits_{k=1}^n\frac{2k-1}{2k} $ https://planetmath.org/integrationofrationalfunctionofsineandcosine
1 http://www.proofwiki.org/wiki/Opposite_Group An 'opposite' or 'dual' group? probably https://proofwiki.org/wiki/Opposite_Group_is_Group but no hits in wayback at all. There is the PlanetMath page http://planetmath.org/oppositegroup
1 http://www.springer.com/mathematics/algebra/book/978-3-642-03979-9 Problem from Victor Prasolov's Polynomials -- Finding the number of real roots of $nx^{n}-x^{n-1}-\cdots -1$ no hits in wayback; but clearly about the book https://zbmath.org/?q=an%3A1272.12001 also should add that pg41 is where the problem is stated
canned edit message Fixing broken link; see Old Links to PlanetMath have Broken https://planetmath.org/alphabetical.html
Calvin Khor
  • 36.6k
  • 1
  • 26
  • 46