Bio
I am the creator of Math Woods. Thank you for joining ! My interests are algebraic topology, group theory, mathematical physics, and many more. Feel free to contact me if you have suggestions for the site or if you want to discuss mathematics !
Problems
Racines carrées de l’unitéFRDeux rectangles superposésFRA la recherche d’antécédentsFRImage ou antécédent ?FRExemples d’images par une fonctionFRExistence d’une racine carréeFRReconnaître une médiatriceFRUne définition équivalente de -groupeFRCarrés dans un anneauFREgalité avec des parenthèsesFRUne division et une multiplicationFRUne addition et une soustractionFRAn easy additionDes exemples de nombres décimauxFRInverse d’une matrice diagonale FRInversibilité de la matrice nulle ?FRScoop sur la caractérisation des sous-groupes distinguésFRDes exemples du théorème des restes chinois ?FRMultiplicativité de la conjugaison complexeFRAdditivité de la conjugaison complexeFRCoins in the riverHolomorphie de la fonction carré ?FRA bad deal in French TarotExemples de matrices inversibles ?FRDiagonalisabilité de l’identité ?FRExamples of singletonsProduit cartésien de singletonsFRProduit de matrices diagonalesFRCommutativité du produit cartésien ?FRExemples simples de matrices diagonalesFRCompacité des ensembles finisFRTriangles isocèles et équilatérauxFREquality with rootsGoldbach’s conjectureConvex sets are simply connectedA simple path homotopyA simple example of homotopyPartial solar eclipseA simple homeomorphism?Field extensions of of degree 2The four chestsThe three chestsThe missing coinDetermining a Hankel matrixField extension of of odd degreeThe golden imposterGroup of -automorphisms-automorphisms of Field homomorphisms from to The twisted shadowsRational power of 2The wooden cubeEquivalence between geometrical and analytical definitions of an ellipseEquations of an ellipse ?The discrete metric1 minute left for this integralThe park problem 2Nar-mayas and the caravan masterPolynomials or not?Degree of easy polynomialsEquality of simple matricesAn easy example of a matrixUnicity of the identity elementSquare of an odd numberSlicing chocolate barsDiscrete topological manifoldsA cyclic system of congruencesQuotient of a group and subgroupA simpler Pythagorean theoremFraction over 100Eigenvalues of orthogonal matricesEigenvalues of a weird matrixIs the parabola reducible ?An equation solvable by radicals ?7-adic yearMagnitude of a root of a polynomialDeterminant of a gcd matrixReal roots and derivative polynomialRoots of the derivative of a quadratic polynomialInterior of a vector subspaceRing with cubic elementsA reasoning on compactnessMiddle or sides ?An intimidating towerAn unfamiliar inner productFunctor between integers with divisibility and groupsGroups of order 2026Limit of a periodic functionGroups of order 6Divisibility of an even numberConsecutive integers and divisibilityFinite groups with 2 conjugacy classesGroups with a single conjugacy classEven-odd equalitySine of a divisor of πRationality of the golden ratioGroups of order 41Number of solutions of a Diophantine equationFixed points of a direct isometryLinear maps of rank 0Roots of a quadratic equation with a parameterLimit of a sum of periodic functionsFinite groups with 3 conjugacy classesA perplexity of eggsBinomial coefficient identity with a bijectionDeterminant of a matrix with consecutive integersEndomorphism with all eigenvectorsA diagonalizable matrix ?Four consecutive integersA price goes up and then downHidden fractionsIntegers as consecutive sums
Solutions written · 78
Racines carrées de l’unitéFRTrois points sur la sphèreFRA la recherche d’antécédentsFRImage ou antécédent ?FRExemples d’images par une fonctionFRRetrouver le centre d’un cercle à partir d’un arc de cercleFRExistence d’une racine carréeFREgalité avec des parenthèsesFRUne division et une multiplicationFRUne addition et une soustractionFRUne addition facileFRInversibilité de la matrice nulle ?FRScoop sur la caractérisation des sous-groupes distinguésFRDes exemples du théorème des restes chinois ?FRGeometric determination of a solution to the equation A bad deal in French TarotDiagonalisabilité de l’identité ?FRDes saut(erelle)sFRCommutativité du produit cartésien ?FRExemples simples de matrices diagonalesFRCompacité des ensembles finisFRDivisibilité d’entiers consécutifsFRConnexité de FRContinuity of differentiationSequences whose terms are getting closer and closerSuites dont les termes se rapprochentFRConvex sets are simply connectedA simple path homotopyA simple example of homotopyPartial solar eclipseAn early estimate of in ancient EgyptLes affres des cadeaux communsFRThe agony of group giftsUne première estimation de dans la culture antique égyptienneFRLes quatre coffresFRFractions cachéesFRField extensions of of degree 2The three chestsThe four chestsThe missing coinDetermining a Hankel matrixField extension of of odd degree-automorphisms of Field homomorphisms from to Rational power of 2Equations of an ellipse ?The park problemThe park problem 2Nar-mayas and the caravan masterOn camels and dromedariesPolynomials or not?Degree of easy polynomialsEquality of simple matricesAn easy example of a matrixUnicity of the identity elementSquare of an odd numberHow to split a chocolate barQuotient of a group and subgroupUn prix qui augmente puis diminueFREntiers comme sommes consécutivesFREquality of areas in a triangleHidden fractionsEigenvalues of a weird matrixDeterminant of a gcd matrixAn unfamiliar inner productLimit of a sum of periodic functionsLimit of a periodic functionDivisibility of an even numberIntegers as consecutive sumsEven-odd equalityGroups of order 41Quick exercise on set theoryFixed points of a direct isometryLinear maps of rank 0Roots of a quadratic equation with a parameterA diagonalizable matrix ?Four consecutive integersA price goes up and then down
Concepts written · 300
Angles adjacentsFREspace métrique completFREspace de BanachFRImage d’un élémentFRMédiatriceFRSuperposabilitéFRAntécédentFRLoi uniformeFRCaractère d’un groupeFRDeuxième théorème de SylowFRPremier théorème de SylowFRCentre d’un groupeFRGroupe simpleFRRapportFRMultipleFRParenthèsesFRDivisionFRMultiplicationFRSoustractionFRAdditionFRNombre décimalFRMatrice nulleFRMatrice nilpotenteFRThéorème des restes chinoisFRConjugué d’un nombre complexeFRReprésentation d’un groupeFRScalarConstruction à la règle et au compasFRFonction holomorpheFRPolygone régulierFRMatrice identitéFRMatrice inversibleFRMatrice diagonalisableFREnsemble discretFRFonction méromorpheFREnsemble finiFRProduit cartésienFRMatrice diagonaleFRTriangle isocèleFRTriangle équilatéralFRRétraction par déformationFRRétractionFRIsométrieFRMatrice orthogonaleFRNormMoyenne proportionnelleFRSimply connected spaceFundamental group of the circlePath homotopyLoop in a spaceHomotopyPreimagePath-connected spaceConnected spacePath in a spaceWeierstrass approximation theoremIrreducible polynomialDegree of a polynomialTower lawIntermediate value theoremHankel matrixLimitDegree of a field extension-automorphismRational numberSylow -subgroup-group-subgroupFundamental theorem of algebraSphereUnit sphereTangent curvesCurveCircleOdd functionEven functionIntervalSymmetryDiscrete topologyIdentity elementStructureFractionClosureSquare of a numberCauchy sequenceDense subsetSubgroups of the realsClosed intervalSubsequential limitSubsequenceStrictly increasing sequenceIncreasing functionSequenceIntersection of setsArbitrary unionSingletonClosed setComplement of a subsetHomeomorphismInverse of a mapContinuous mapSecond-countable spaceCountable setBase of a topologyHausdorff spaceDisjoint setsOpen neighborhoodManifoldLie groupSmooth mapMultiplicity of a rootSimple rootNatural bijectionNatural isomorphismCovariant functorPre-compositionContravariant hom functorPost-compositionCovariant hom functorHom functorLocally small categoryQuotient groupNormal subgroupTopology (domain)Group theoryMetric spaceMetricEmpty setConjectureHypotenuseRight trianglePythagorean theoremOrbit-stabiliser theoremBurnside’s lemmaFinite groupOrbit of a group actionLeft cosetWell-defined mapGroup actionWalk in a graphEdge of a graphChinese remainder theoremCongruence modulo FRFactorFundamental theorem of arithmeticEuclid’s lemmaBézout’s identityEuclidean divisionVertex of a graphFinite graphDirected graphRotationComposite numberNatural numberOdd numberEven numberCharacteristic polynomial of a matrixCharacteristic polynomial of an endomorphismCharacteristic polynomialDiscriminantEigenvalueEigenvectorProjective spaceTorusSmooth manifoldTopological manifoldDifferential formTensor product of vector spacesTensorTensor fieldDivergence of a vector fieldCurl of a vector fieldGradientSchrödinger’s equationPoincaré sphereBloch sphereVan Kampen’s theoremFundamental groupNatural transformationTransition map of a fiber bundleTransition map of a manifoldHopf fibrationPrincipal bundleFiber bundleVector bundleInclusionTriangleMedian of a triangleComposition of mapsTopology on a setOpen setImaginary unitReal numberEigenvalue of a matrixEigenvalue of an endomorphismModulusComplex numberBinomial coefficientCardinalElementary symmetric polynomialSymmetric polynomialPermutationProper subsetParabolaReducible algebraic setRadical idealRadical of an idealVanishing idealHilbert’s weak NullstellensatzIdeal generated by polynomialsAlgebraically closed fieldMaximal idealIdealAlgebraic setZero locusAffine space over a fieldPolynomial ringSeparable field extensionFunctionCartesian productSet theoryIndex of a subgroupOrder of a finite groupDivisibilityNormal field extensionSubfieldImage of a mapField extensionField homomorphismSolvability by radicals of a polynomialGalois group of a polynomialSplitting field-morphismGalois group of a field extensionFixing subgroup of an intermediate fieldFixed field of a subgroupGalois correspondence theoremIntermediate fieldSubgroupFinite field extensionGalois extensionTranspose of a matrixSymmetric matrixInner productTraceSquare matrixMatrixOrder of an element of a groupAbelian groupBijective mapSurjective mapInjective mapMapGroup homomorphismConjugate elementsLinear mapp-adic numberEuler’s totient functionRolle’s theoremCommutative ringPolyhedronPlatonic solidRingRoot of a polynomialQuadratic polynomialPolynomialConvex hullConvex setSegmentInterior of a subsetSubsetVector subspaceNormed vector spaceVector spaceTopological spaceCompact spacePrime numberCategory of groupsFunctorCategoryPosetTransitive relationAntisymmetric relationAntisymmetric relationReflexive relationRelation (set theory)SetFieldPeriodic functionGroup isomorphismConjugacy classPermutation groupCyclic groupConjugacy classGroupElement expressible by radicalsGolden ratioLagrange’s theoremIntegerEndomorphism