| U-duality | RR09BM3F8Z | unknown | open | Wikidata Q4001392, nLab U-duality |
| U-statistic | VHGSCR4CD0 | unknown | open | Wikidata Q7862949, MathWorld U-Statistic |
| U/u | Y2TERR74CB | unknown | out_of_scope (a notation: the notation register holds it (corpus spec K10.4)) | Wikidata Q9747, ProofWiki Symbols:U |
| Uban number | PHE8D4P950 | object | open | Wikidata Q120336340, MathWorld UbanNumber, OEIS A089590 |
| Ugo Dal Lago | G8QAE04V6K | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q93944804, nLab Ugo Dal Lago |
| Ukraine | 460DA37J2A | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q212, ProofWiki Mathematician:Mathematicians/Sorted_By_Nation/Ukraine |
| Ulam number | KYHY6BX74S | concept | open | Wikidata Q1784026, MathWorld UlamSequence |
| Ulam spiral | 7AYVNHTMH8 | concept | open | Wikidata Q842172, MathWorld PrimeSpiral, OEIS A143856 |
| Ulf Lindström | 1MQE7FMTGC | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q7878891, nLab Ulf Lindström |
| Uli Wagner | 1J3NG4Y7FA | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q57637964, nLab Uli Wagner |
| Ulrich Bunke | A2MM3NMKJH | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q15303086, nLab Ulrich Bunke |
| Ulrich Güntzer | P8W6WPAZ42 | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q38222960, nLab Ulrich Güntzer |
| Ulrik Buchholtz | 5AGF4J5KRM | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q59749232, nLab Ulrik Buchholtz |
| Ulrike Tillmann | 810H5AKNZF | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q92006, nLab Ulrike Tillmann |
| ultrafilter | 8TR7GEFQC2 | concept | open | Wikidata Q1571831, EoM Ultrafilter, MathWorld Ultrafilter, nLab ultrafilter |
| ultrametric space | H250HT01XR | unknown | open | Wikidata Q1897429, MathWorld Ultrametric |
| ultrapower | 76J9Y0E0DB | unknown | open | Wikidata Q124222093, MathWorld Ultrapower |
| ultraproduct | MVDDHPZV2Y | unknown | open | Wikidata Q1535225, MathWorld Ultraproduct, nLab ultraproduct |
| ultraviolet catastrophe | WH0D1G5QZQ | unknown | open | Wikidata Q1399710, nLab ultraviolet catastrophe |
| ultraviolet divergence | PKJCHT14K5 | unknown | open | Wikidata Q3032228, nLab ultraviolet divergence |
| ultraweak topology | K8KT8H2JA5 | unknown | open | Wikidata Q7880722, nLab ultraweak topology |
| Umberto Bottazzini | R59HPPCWSX | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q2478100, nLab Umberto Bottazzini |
| umbilical point | D24G65DQZB | unknown | open | Wikidata Q3351935, MathWorld UmbilicPoint |
| umbral calculus | 92Y4V0A3B7 | definition | open | Wikidata Q1055314, MathWorld UmbralCalculus, nLab umbral calculus, ProofWiki Definition:Umbral_Calculus |
| umbral moonshine | JPTP2EA3XP | unknown | open | Wikidata Q7881385, nLab umbral moonshine |
| unary function | KEV4XN4GK1 | unknown | open | Wikidata Q7882311, MathWorld UnivariateFunction |
| unary operation | DKV1N5R17B | unknown | open | Wikidata Q657596, MathWorld UnaryOperation |
| unary relation | 5WTZG0M35F | definition | open | Wikidata Q134514179, ProofWiki Definition:Relation/Unary_Relation |
| unbiased estimator | RJ6WY8X663 | unknown | open | Wikidata Q112892869, MathWorld UnbiasedEstimator |
| unbounded operator | 33QAJMXS73 | unknown | open | Wikidata Q5108738, EoM Unbounded_operator, nLab unbounded operator |
| uncertainty principle | 8S3D313WFX | unknown | open | Wikidata Q44746, EoM Uncertainty_principle, nLab uncertainty principle |
| uncia | 93QBYFCDW7 | unknown | open | Wikidata Q1645564, MathWorld Uncia |
| uncorrelatedness | EBFM6PHTBJ | unknown | open | Wikidata Q8216221, MathWorld Uncorrelated |
| uncountable set | CZFSMSCHK0 | definition | open | Wikidata Q1128796, ProofWiki Definition:Uncountable_Set |
| uncountably infinite set | 85KQYKC2CB | unknown | open | Wikidata Q141102737, MathWorld UncountablyInfinite |
| undecidable problem | W3JXKPA6AQ | unknown | open | Wikidata Q3502995, MathWorld RecursivelyUndecidable |
| undecimal | ZEQ4WXCYVX | definition | open | Wikidata Q5357322, ProofWiki Definition:Undecimal_Notation |
| undefined | XWF0KZY6QK | concept | open | Wikidata Q7883028, MathWorld Undefined |
| underlying set | EHE3HKK8SW | unknown | open | Wikidata Q2456981, nLab underlying set |
| Understanding Physics | P3X2GWVN7W | unknown | out_of_scope (a book, not an item of mathematics) | Wikidata Q7883795, ProofWiki Book:Isaac_Asimov/Understanding_Physics |
| undirected graph | XQT8D9FF6N | concept | open | Wikidata Q3115587, MathWorld UndirectedGraph |
| undulating number | A377ZTSZFB | unknown | open | Wikidata Q3343081, MathWorld UndulatingNumber, OEIS A033619 |
| unexpected hanging paradox | Q0PANNVY6S | unknown | open | Wikidata Q1142663, MathWorld UnexpectedHangingParadox |
| unicoherent space | 4MCGY2XW14 | concept | open | Wikidata Q7884743, MathWorld UnicoherentSpace |
| unicyclic graph | YBE5DZHNJ1 | unknown | open | Wikidata Q137545222, MathWorld UnicyclicGraph |
| unification | 7F5KRHDAMQ | unknown | open | Wikidata Q609057, MathWorld Unification |
| uniform boundedness principle | DN0X0A5JRX | statement | open | Wikidata Q1426292, EoM Banach-Steinhaus_theorem, MathWorld Banach-SteinhausTheorem, ProofWiki Banach-Steinhaus_Theorem |
| uniform coloring | 5QXPFTR99A | unknown | open | Wikidata Q7885098, MathWorld PolyhedronColoring |
| uniform continuity | 7ZJYA8EKE9 | concept | open | Wikidata Q741865, EoM Uniform_continuity, MathWorld UniformlyContinuous |
| uniform convergence | KYNMF0N33A | unknown | open | Wikidata Q1411887, EoM Uniform_convergence, Mathlib TendstoUniformly, MathWorld UniformConvergence, nLab uniform convergence |
| uniform integrability | Q8YR2DH2C6 | concept | open | Wikidata Q1530275, EoM De_la_Vallée-Poussin_theorem |
| uniform limit theorem | V68R5TQ9D5 | statement | open | Wikidata Q7885107, ProofWiki Uniform_Limit_Theorem |
| uniform module | 19BYYTGFT5 | unknown | open | Wikidata Q7885110, nLab uniform module |
| uniform norm | 581JBERAYY | unknown | open | Wikidata Q1202673, MathWorld SupremumNorm |
| uniform polyhedron | 7MG9WN8ZCZ | unknown | open | Wikidata Q2471563, MathWorld UniformPolyhedron |
| uniform property | 1XNT8BGBFQ | unknown | open | Wikidata Q2281389, nLab uniform property |
| uniform space | F7K2JFG7NB | unknown | open | Wikidata Q652446, EoM Uniform_space, Mathlib UniformSpace, nLab uniform space |
| uniform tiling | GXAVPRRFFG | unknown | open | Wikidata Q7885119, MathWorld UniformTessellation |
| uniformitarianism | 6TNS4SBHHB | statement | open | Wikidata Q208650, ProofWiki Principle_of_Uniformity_of_Nature |
| uniformly Cauchy sequence | KAT64SBSMV | concept | open | Wikidata Q7885144, MathWorld UniformlyCauchy |
| uniformly convergent series | Z920VSR23B | unknown | open | Wikidata Q91257411, EoM Uniformly-convergent_series |
| uniformly convex space | 5KW7DPC3WZ | unknown | open | Wikidata Q847535, MathWorld UniformlyConvex |
| uniformly hyperfinite algebra | 8YF8MZ3ZAB | unknown | open | Wikidata Q2467095, nLab uniformly hyperfinite algebra |
| unigraph | PPR8RWD6XW | unknown | open | Wikidata Q130473407, MathWorld UnigraphicGraph |
| unimodal distribution | 4W0M03NYYZ | unknown | open | Wikidata Q124178356, EoM Unimodal_distribution, MathWorld UnimodalDistribution |
| unimodal sequence | FNJW1J0CFE | unknown | open | Wikidata Q110277478, MathWorld UnimodalSequence |
| unimodality | JXTE3334MZ | unknown | open | Wikidata Q2896771, MathWorld Unimodal |
| unimodular group | RV32YZYA7V | unknown | open | Wikidata Q124178631, EoM Unimodular_group, MathWorld UnimodularGroup |
| unimodular lattice | VVNZGX5TW9 | unknown | open | Wikidata Q2794475, LMFDB knowl lattice.unimodular |
| unimodular matrix | FA6MN9VDZ1 | unknown | open | Wikidata Q1367055, MathWorld UnimodularMatrix |
| union | E768EJCYWC | unknown | open | Wikidata Q185359, MathWorld Union |
| Union-closed sets conjecture | 7MPQRGDZHX | conjecture | open | Wikidata Q2993338, MathWorld Union-ClosedSetsConjecture |
| unipotent matrix | T100K0P91B | unknown | open | Wikidata Q2494911, MathWorld Unipotent |
| unique factorization domain | XAMX9JNA4M | definition | open | Wikidata Q1052579, LMFDB knowl ring.unique_factorization_domain, Mathlib UniqueFactorizationMonoid, MathWorld UniqueFactorizationDomain, ProofWiki Definition:Unique_Factorization_Domain |
| unique prime | TXXZ8B57YB | unknown | open | Wikidata Q2654418, MathWorld UniquePrime, OEIS A040017 |
| uniquely colorable graph | 8H61EQJH7V | unknown | open | Wikidata Q7886960, MathWorld UniquelyColorableGraph |
| uniquely embeddable graph | QE5C1PPSCQ | unknown | open | Wikidata Q130323039, MathWorld UniquelyEmbeddableGraph, OEIS A372853 |
| uniquely Hamiltonian graph | 6PF6CEV9JF | unknown | open | Wikidata Q130598732, MathWorld UniquelyHamiltonianGraph |
| uniquely pancyclic graph | BQVVSD3ZT7 | unknown | open | Wikidata Q130598728, MathWorld UniquelyPancyclicGraph |
| uniqueness | FCE1QW85T4 | topic | open | Wikidata Q17548110 |
| uniqueness quantification | JNACNVQHC8 | unknown | open | Wikidata Q2502253, MathWorld Unique, nLab uniqueness quantifier |
| uniqueness theorem | TPYT3GNJQW | definition | open | Wikidata Q26261907, MathWorld UniquenessTheorem, ProofWiki Definition:Uniqueness_Theorem |
| unit | A1RWYB5XHC | concept | open | Wikidata Q118084, LMFDB knowl ring.unit, MathWorld RingUnit, MathWorld Unit, nLab unit |
| unit ball | 2JF2SZY02Q | unknown | open | Wikidata Q105332556, MathWorld UnitBall, nLab unit ball |
| unit cell | WHY1DVR7YE | unknown | open | Wikidata Q11878049, MathWorld UnitCell |
| unit circle | J6WN0BY43N | unknown | open | Wikidata Q203425, MathWorld UnitCircle |
| unit cube | 8BBSYCA7AY | unknown | open | Wikidata Q2072112, MathWorld UnitCube |
| unit disk | 8ZBM3Y3NH5 | unknown | open | Wikidata Q2390323, MathWorld UnitDisk |
| unit distance graph | F6NY4NW54G | unknown | open | Wikidata Q745378, MathWorld Unit-DistanceGraph |
| unit fraction | 7Y0VPG60TV | definition | open | Wikidata Q255388, EoM Aliquot_ratio, MathWorld UnitFraction, ProofWiki Definition:Unit_Fraction |
| unit interval | FW0B04RJMB | unknown | open | Wikidata Q1987578, MathWorld UnitInterval |
| unit of force | C5Q4A3A0DB | definition | open | Wikidata Q15976022, ProofWiki Definition:SI/Force |
| unit of measurement | FG6H2M3T2S | definition | open | Wikidata Q47574, ProofWiki Definition:Unit_of_Measurement |
| unit of pressure | 4F4YYBRNGM | definition | open | Wikidata Q4173969, ProofWiki Definition:Pressure/Unit |
| unit of speed | STPAF1D3X5 | definition | open | Wikidata Q15222637, ProofWiki Definition:Velocity/Unit |
| unit sphere | P0Z9GE0VMR | unknown | open | Wikidata Q1307800, MathWorld UnitSphere, nLab unit sphere |
| unit square | Z0NA8ERR13 | unknown | open | Wikidata Q1307838, MathWorld UnitSquare |
| unit type | 4GDDB3E4J3 | unknown | open | Wikidata Q1307872, nLab unit type |
| unit vector | H5J392GZNH | definition | open | Wikidata Q36255, MathWorld UnitVector, nLab unit vector, ProofWiki Definition:Unit_Vector |
| unital magma | 406YZA61A4 | definition | open | Wikidata Q111485852, ProofWiki Definition:Unital_Magma |
| unitary character | ZSSD4NYEMQ | unknown | open | Wikidata Q77982137, MathWorld UnitaryMultiplicativeCharacter |
| unitary divisor | 6DTV591B6B | concept | open | Wikidata Q1704865, MathWorld UnitaryDivisor |
| unitary element | ZBY6CAMDS8 | concept | open | Wikidata Q104841236, MathWorld UnitaryElement |
| unitary group | 252919GDDQ | definition | open | Wikidata Q1500617, EoM Unitary_group, MathWorld UnitaryGroup, nLab unitary group, ProofWiki Definition:Unitary_Group |
| unitary matrix | YNRSTBKDN5 | unknown | open | Wikidata Q727103, EoM Unitary_matrix, MathWorld UnitaryMatrix, nLab unitary matrix |
| unitary operator | NK2S60NT68 | unknown | open | Wikidata Q1972470, EoM Unitary_operator, MathWorld Unitary |
| unitary perfect number | AJZ14GMQ7M | unknown | open | Wikidata Q2370031, MathWorld UnitaryPerfectNumber, OEIS A002827 |
| unitary representation | JDS06W78JR | topic | open | Wikidata Q10359539, nLab unitary representation |
| unitary transformation | 6YBPK7243E | unknown | open | Wikidata Q2495534, MathWorld UnitaryTransformation |
| United Kingdom | 16MM0D8RZ7 | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q145, ProofWiki Mathematician:Mathematicians/Sorted_By_Nation/Britain |
| United States | C3NAD916J0 | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q30, ProofWiki Mathematician:Mathematicians/Sorted_By_Nation/United_States |
| univalent function | KWYMECV6MY | unknown | open | Wikidata Q2608535, MathWorld UnivalentFunction |
| univariate | C26RAD6GY8 | unknown | open | Wikidata Q1681619, MathWorld Univariate |
| univariate polynomial | ZDF7J61TDE | unknown | open | Wikidata Q91031942, MathWorld UnivariatePolynomial |
| universal algebra | G6NVAYV9AD | topic | open | Wikidata Q1636734, EoM Universal_algebra, MathWorld UniversalAlgebra |
| universal bundle | 1XP2HQB72Q | unknown | open | Wikidata Q7894108, nLab universal bundle |
| universal central extension | ASJ91Z6VQE | unknown | open | Wikidata Q114145346, nLab universal central extension |
| universal class | TXPJ5BJW7B | definition | open | Wikidata Q2649292, ProofWiki Definition:Universal_Class |
| universal closure | 71K9EQ3GGQ | definition | open | Wikidata Q9209930, ProofWiki Definition:Universal_Closure_of_Well-Formed_Formula |
| universal coefficient theorem | JMAFH6MN0X | statement | open | Wikidata Q2495664, nLab universal coefficient theorem |
| universal cover | K1R7AYJWYG | unknown | open | Wikidata Q4475749, MathWorld UniversalCover, nLab universal covering space |
| universal enveloping algebra | XDECH5ZGS6 | concept | open | Wikidata Q1673406, EoM Universal_enveloping_algebra, nLab universal enveloping algebra |
| Universal Information Hydrodynamics | DJ65ZRVZKF | topic | open | Wikidata Q136913087 |
| universal parabolic constant | K8K9H4SKGK | object | open | Wikidata Q7894145, MathWorld UniversalParabolicConstant, OEIS A103710 |
| Universal Product Code | 9RS9C2JHNZ | unknown | open | Wikidata Q1193047, MathWorld UPC |
| universal property | XDHJEX0R2E | unknown | open | Wikidata Q1417809, EoM Universal_property |
| universal quantification | 3XRQ9Q08MV | unknown | open | Wikidata Q126695, EoM Universal_quantifier, MathWorld UniversalQuantifier, nLab universal quantifier |
| universal sentence | Z45D7RGSRN | unknown | open | Wikidata Q141488365, MathWorld UniversalSentence |
| universal set | ADCAEJFZWS | unknown | open | Wikidata Q1378301, MathWorld UniversalSet |
| universal space | FZJAKS8C4G | unknown | open | Wikidata Q20878963, MathWorld UniversalSpace |
| universal Turing machine | 6HDAEY63HK | concept | open | Wikidata Q2703890, MathWorld UniversalTuringMachine |
| universality class | VM7EQMZYPC | concept | open | Wikidata Q25098515, MathWorld UniversalityClass, nLab universality class |
| universe | 1TM215FP1W | concept | open | Wikidata Q597663, ProofWiki Definition:Universe_(Set_Theory) |
| universe | RVGE8HR01H | definition | open | Wikidata Q1, ProofWiki Definition:Physical_Universe |
| unknot | CZ4PZSG5CN | unknown | open | Wikidata Q1188344, MathWorld Unknot, nLab unknot |
| unknotting number | QCM0RAAED5 | unknown | open | Wikidata Q7896949, MathWorld UnknottingNumber, nLab unknotting number |
| unlink | 61ASXBN62B | unknown | open | Wikidata Q2791199, MathWorld Unlink |
| unordered pair | 8RTB58KFDP | unknown | open | Wikidata Q1477744, MathWorld Pair, nLab unordered pair |
| unramified morphism | N8RYPTETX6 | unknown | open | Wikidata Q85812355, nLab unramified morphism |
| untouchable number | PEECP8G6Y4 | unknown | open | Wikidata Q1193504, MathWorld UntouchableNumber, OEIS A005114 |
| unusual number | EX45NAGXXC | unknown | open | Wikidata Q1755492, MathWorld UnusualNumber, OEIS A064052 |
| up quark | PQFB82T4TK | unknown | open | Wikidata Q6732, nLab up quark |
| upper and lower topology | JXGYMM0JYK | concept | open | Wikidata Q120358757, nLab semicontinuous topology |
| upper bound | 2SH3G397TB | unknown | open | Wikidata Q42866132, MathWorld UpperBound, nLab upper bound |
| upper domination number | 7NFNBQG9R2 | unknown | open | Wikidata Q130405721, MathWorld UpperDominationNumber |
| upper half-plane | FJF15JH537 | unknown | open | Wikidata Q3258885, LMFDB knowl mf.upper_half_plane, MathWorld UpperHalf-Plane, nLab upper half-plane |
| upper irredundance number | PNW372RZMS | unknown | open | Wikidata Q130486997, MathWorld UpperIrredundanceNumber |
| upper set | VPPP3A9W66 | unknown | open | Wikidata Q2528262, nLab upper set |
| upper triangular matrix | 1W8C1QV0S3 | unknown | open | Wikidata Q77968835, MathWorld UpperTriangularMatrix |
| uranium | AWFYN1K7T5 | definition | open | Wikidata Q1098, ProofWiki Definition:Uranium |
| uranium-238 | WVJN70G8JP | definition | open | Wikidata Q1148503, ProofWiki Definition:Uranium/238 |
| Uranus | ZG0MTQSEM7 | definition | open | Wikidata Q324, ProofWiki Definition:Uranus |
| urelement | 4DRPCTKHQB | unknown | open | Wikidata Q1896657, MathWorld Urelement, nLab urelement |
| urn problem | A1FHD0K17C | problem | open | Wikidata Q36938, MathWorld BallPicking |
| Urs Schreiber | DQGTF4YFMX | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q16875354, nLab Urs Schreiber |
| Urtzi Buijs | ES2FJW5TGJ | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q102292256, nLab Urtzi Buijs |
| Uruguay | 754ZZV1DE1 | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q77, ProofWiki Mathematician:Mathematicians/Sorted_By_Nation/Uruguay |
| Urysohn space | JYJ15AS7ED | concept | open | Wikidata Q1629844, ProofWiki Definition:Completely_Hausdorff_Space |
| Urysohn's lemma | 9WSFAS4Q12 | statement | open | Wikidata Q1816967, EoM Urysohn_lemma, Mathlib exists_continuous_zero_one_of_isClosed, MathWorld UrysohnsLemma, nLab Urysohn's lemma |
| utility graph | KWGJ0ZAZV1 | unknown | open | Wikidata Q123375397, House of Graphs 84, MathWorld UtilityGraph |
| Uwe Jannsen | ST7WFBQKF0 | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q2504324, nLab Uwe Jannsen |
| Uzbekistan | RV2QB8W9B3 | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q265, ProofWiki Mathematician:Mathematicians/Sorted_By_Nation/Uzbekistan |