| Olof B. Widlund | 63YY5TY80D | topic | open | Wikipedia Olof B. Widlund, Wikidata Q7088470 |
| Olof B. Widlund Prize | QGQCDWRER0 | unknown | open | Wikipedia Olof B. Widlund#4TM7 |
| Olof Staffans | ARCJ7XSN87 | unknown | open | Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#5VOH |
| Olog | C5XT16M2X0 | definition | open | Wikipedia Olog, Wikidata Q7088492 |
| Oloid | 8BGK9Z6D31 | unknown | open | Wikipedia List of mathematical shapes#2IWN |
| oloid | BCY36YMNKF | unknown | open | Wikidata Q1751494, MathWorld Oloid |
| Olry Terquem | X25AG6DAMV | topic | open | Wikipedia List of Jewish mathematicians#ZS3E |
| Olry Terquem | YZHT590BRR | topic | open | Wikipedia Olry Terquem, Wikidata Q245572 |
| Olshansky, S. Jay | 9913WVKMAX | unknown | open | Wikipedia List of statisticians#WNZB |
| Olvi L. Mangasarian | BMYE263MZ8 | topic | open | Wikipedia Olvi L. Mangasarian, Wikidata Q15837516 |
| Olympia Heights | ZTFCZ50T8F | unknown | open | Wikipedia List of U.S. communities with Hispanic-majority populations in the 2000 census#DMRV |
| Olympia Nicodemi | YDGD9N5NX7 | topic | open | Wikipedia Olympia Nicodemi, Wikidata Q48970163 |
| Olympiade Mathématique Belge | 4MS58H1APJ | unknown | open | Wikipedia List of mathematics competitions#RW8P |
| Olympic gel | 9M5NK688GN | definition | open | Wikipedia Olympic gel, Wikidata Q136171470 |
| Omar Catunda | TS6ARTTXW6 | topic | open | Wikipedia Omar Catunda, Wikidata Q10340809 |
| Omar Khayyam | AM3K84JD3K | topic | open | Wikipedia List of geometers#8AX1 |
| Omar Khayyám | GXP58G7WKZ | topic | out_of_scope (a person, not an item of mathematics) | Wikidata Q35900, ProofWiki Mathematician:Omar_Khayyam, Wikipedia Omar Khayyam |
| ombilic | Z9KCQK6GXC | definition | open | Wikipedia Glossary of classical algebraic geometry#21LI |
| OMDoc | GYGBY1DG37 | definition | open | Wikipedia OMDoc, Wikidata Q268086 |
| Omega | 7P1EA02YT1 | definition | open | Wikipedia List of numbers#NS4G |
| omega | JPK5ADFK6V | definition | open | Wikipedia Glossary of mathematical symbols#TPN4 |
| Omega and agemo subgroup | DFHBYF0GYG | definition | open | Wikipedia Omega and agemo subgroup, Wikidata Q7090038 |
| omega constant | BGT91H1HZQ | definition | open | Wikidata Q2291098, MathWorld OmegaConstant, OEIS A030178, Wikipedia Omega constant |
| Omega language | 7KKJ6GMDZN | definition | open | Wikipedia Omega language, Wikidata Q4334568 |
| Omega logic | 1RYMKVRB3H | definition | open | Wikipedia Glossary of set theory#Z9G5 |
| Omega process | WSQCZ569MH | definition | open | Wikipedia Glossary of invariant theory#CDDR |
| Omega triangle | Q1F4HVF42A | unknown | open | Wikipedia Hyperbolic triangle#740E |
| Omega-categorical theory | 1FGM3P0KN0 | definition | open | Wikipedia Omega-categorical theory, Wikidata Q7089964 |
| omega-limit sets | MR6D6RD2Y9 | unknown | open | mathlib_overview Dynamics > General theory > omega-limit sets, Mathlib omegaLimit |
| Omega-regular language | 2D7XFBAK76 | definition | open | Wikipedia Omega-regular language, Wikidata Q309558 |
| Omega-rule | 1MHYHZSXDX | unknown | open | Wikipedia Ω-consistent theory#W1CN |
| OMEMO | ZQ5VMCSFN3 | definition | open | Wikipedia OMEMO, Wikidata Q22907457 |
| Omen | XAKHAEMPY5 | definition | open | Wikipedia Omen, Wikidata Q1120735 |
| Omer Reingold | WYNRV845R9 | unknown | open | Wikipedia List of people by Erdős number#6EIE, Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#SYM5 |
| Omidali and Rahmati | GR144TD120 | statement | record (an item of a paper that no node asks for yet. The record keeps its edges in the record plane (corpus arxiv AX8.6)) | arXiv 2610.02495#DDSW |
| Omission bias | EAZK8VA4QP | unknown | open | Wikipedia List of cognitive biases#O6KR |
| Omitted-variable bias | QPSRDDQ34F | definition | open | Wikipedia List of statistics articles#SZQL |
| Omitted-variable bias | WBQ2PASG2D | definition | open | Wikipedia Omitted-variable bias, Wikidata Q3274486 |
| Omitting types theorem | 6R21FMFC5H | statement | open | Wikipedia Type (model theory)#1VSE |
| Omnibus test | PEWBB3ECTB | definition | open | Wikipedia Omnibus test, Wikidata Q1669154 |
| Omnibus test | XQBX26MZK2 | definition | open | Wikipedia List of statistics articles#3P2A |
| Omnipotence does not mean breaking the laws of logic | YX181G8CYH | statement | open | Wikipedia Omnipotence paradox#ZFHC |
| Omnipotence paradox | 440XSRAMBE | statement | open | Wikipedia Omnipotence paradox, Wikidata Q834848 |
| Omnipotent | SVZ2TNRCH7 | unknown | open | Wikipedia List of paradoxes#I8ZA |
| Omniscient | 9RT38MVW6V | unknown | open | Wikipedia List of paradoxes#TW2H |
| Omnitruncated 5-cell honeycomb | CXPQVER3QZ | definition | open | Wikipedia List of mathematical shapes#F888, Wikipedia List of polygons, polyhedra and polytopes#KPS4 |
| Omnitruncated 5-simplex honeycomb | 6Q76FHGT0Z | object | open | Wikipedia List of mathematical shapes#WH12, Wikipedia List of polygons, polyhedra and polytopes#VB0X |
| Omnitruncated 5-simplex honeycomb | XAAFVBG01K | object | open | Wikipedia Omnitruncated 5-simplex honeycomb, Wikidata Q7090406 |
| Omnitruncated 6-simplex honeycomb | X0VT28E6Z7 | definition | open | Wikipedia Omnitruncated 6-simplex honeycomb, Wikidata Q7090409 |
| Omnitruncated cubic honeycomb | RCKQ3TJG72 | object | open | Wikipedia List of mathematical shapes#MHCX, Wikipedia List of polygons, polyhedra and polytopes#QM7Q |
| Omnitruncated order-6 dodecahedral honeycomb | GRACEZHRAX | unknown | open | Wikipedia Order-6 dodecahedral honeycomb#ZMJW |
| Omnitruncated polyhedron | KX6HS3T62A | definition | open | Wikipedia Omnitruncated polyhedron, Wikidata Q7090411 |
| Omnitruncated simplicial honeycomb | WR1DZ04KEA | definition | open | Wikipedia Omnitruncated simplicial honeycomb, Wikidata Q17077760 |
| Omnitruncated tesseractic honeycomb | 8TX6TW4WGZ | definition | open | Wikipedia Omnitruncated tesseractic honeycomb, Wikidata Q17077763 |
| Omnitruncated triangular-hexagonal prismatic honeycomb | 7RDVAX6FJM | definition | open | Wikipedia List of mathematical shapes#OVHO, Wikipedia List of polygons, polyhedra and polytopes#HZYQ |
| Omnitruncation | 4AXW3K8GY1 | definition | open | Wikipedia List of polygons, polyhedra and polytopes#GANX |
| Omnitruncation | D6FCJJXYF8 | definition | open | Wikipedia Omnitruncation, Wikidata Q7090413 |
| Omori's law | GPP674RAM0 | statement | open | Wikipedia Aftershock#XAXE |
| Omori−Yau maximum principle | PMXS03Z0K2 | statement | open | Wikipedia Shing-Tung Yau#006O |
| Omphalos hypothesis | PACZ6JCHZC | statement | open | Wikipedia Falsifiability#NLDM |
| Omri Sarig | 5XB8V900HR | topic | open | Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#WO1H |
| Omri Sarig | ESMH8J4F5E | topic | open | Wikipedia Omri Sarig, Wikidata Q47540126 |
| On | PZ7TSM9JTC | definition | open | Wikipedia Glossary of set theory#7ZSH |
| On $\gcd(|C|, \dim V) = 1$ | KKFHWF52G2 | statement | open | napkin tex/rep-theory/applications.tex#lem:burnside_ant_lemma |
| On Ascensions | Y7BJWJ5S5W | unknown | open | Wikipedia Hypsicles#R8E1 |
| On Conoids and Spheroids | RE0TTZ6QAW | definition | open | Wikipedia On Conoids and Spheroids, Wikidata Q3976738 |
| On Formally Undecidable Propositions of Principia Mathematica and Related Systems | AD82277MD6 | statement | open | Wikipedia List of mathematics books#7XS3 |
| On Formally Undecidable Propositions of Principia Mathematica and Related Systems | B1A6T71HW7 | statement | open | Wikipedia On Formally Undecidable Propositions of Principia Mathematica and Related Systems, Wikidata Q7090984 |
| On Indivisible Lines | Z9H7K3KXTB | definition | open | Wikipedia On Indivisible Lines, Wikidata Q3302740 |
| On Interpretation | 34ZE9DFG7E | definition | open | Wikipedia On Interpretation, Wikidata Q648627 |
| On Interpretation | 366QHCEVXG | definition | open | Wikipedia List of works by Averroes#4XA4 |
| On notations | ZXB09Q40B7 | definition | open | Wikipedia Radical axis#OOJE |
| On Numbers and Games | C6ETD4YHBA | definition | out_of_scope (a book, not an item of mathematics) | Wikidata Q3352152, ProofWiki Book:John_H._Conway/On_Numbers_And_Games, Wikipedia On Numbers and Games |
| On quaternions and octonions | KQDK1CCDMS | unknown | out_of_scope (a book, not an item of mathematics) | Wikidata Q97008688, ProofWiki Book:John_H._Conway/On_Quaternions_And_Octonions |
| On Spirals | 3KZAV7EBV2 | definition | out_of_scope (a book, not an item of mathematics) | Wikidata Q3024233, ProofWiki Book:Archimedes/On_Spirals, Wikipedia On Spirals |
| On the Causes of Plants | 4TPBSV21YP | unknown | open | Wikipedia Theophrastus#P4BM |
| On the Dioptra | K7079JGY08 | unknown | open | Wikipedia Hero of Alexandria#4UMM |
| On the hypothesis | Z2T6YC8NMD | statement | open | Wikipedia Brunn–Minkowski theorem#YOTJ |
| On the Number of Primes Less Than a Given Magnitude | NCS8CF2HQ3 | definition | open | Wikipedia On the Number of Primes Less Than a Given Magnitude, Wikidata Q905091 |
| On the Number of Primes Less Than a Given Magnitude | YZ3TD0ZBNN | definition | open | Wikipedia List of number theory topics#0CTV |
| On the Riemann hypothesis | XM0QAXSJBE | statement | open | Wikipedia Popular mathematics#KIKH |
| On the Sizes and Distances | 8R47C5G1BM | unknown | out_of_scope (a book, not an item of mathematics) | Wikidata Q7091541, ProofWiki Book:Aristarchus_of_Samos/On_the_Sizes_and_Distances_of_the_Sun_and_Moon |
| On the Space-Theory of Matter | NSAH0J8ZCY | unknown | open | Wikidata Q19087159, nLab On the Space-Theory of Matter |
| On the Sphere and Cylinder | 48DC2A7CCA | definition | open | Wikipedia On the Sphere and Cylinder, Wikidata Q2717459 |
| On-Line Encyclopedia of Integer Sequences | QH4T121B29 | definition | open | Wikipedia On-Line Encyclopedia of Integer Sequences, Wikidata Q728415 |
| On-set virtual production | M9FJVB8GYZ | unknown | open | Wikipedia List of computer graphics and descriptive geometry topics#VLL6 |
| Once de Octubre | 21ZDPZVMKH | unknown | open | Wikipedia List of places with numeric names#3078 |
| Once de Septiembre | 7ECA69YZJC | unknown | open | Wikipedia List of places with numeric names#TN7D |
| one | 132WCAJNNM | definition | open | Wikipedia Glossary of functional analysis#Q78V |
| One accelerated phase | F5H9Z0ANAN | statement | record (an item of a paper that no node asks for yet. The record keeps its edges in the record plane (corpus arxiv AX8.6)) | arXiv 2609.32558#EENK |
| one and only one | QNXDN6JPBJ | definition | open | Wikipedia Glossary of mathematical jargon#TPU9 |
| One block step | XNJ0GGB4BA | statement | record (an item of a paper that no node asks for yet. The record keeps its edges in the record plane (corpus arxiv AX8.6)) | arXiv 2610.06810#22R7 |
| One bounded target | MT6FDMFW8A | statement | record (an item of a paper that no node asks for yet. The record keeps its edges in the record plane (corpus arxiv AX8.6)) | arXiv 2610.09640#QAA3 |
| One branching step as a controlled unitary | 5HZPR2DT9Q | example | record (an item of a paper that no node asks for yet. The record keeps its edges in the record plane (corpus arxiv AX8.6)) | arXiv 2609.37375#B5RS |
| One calibrated law with an energy-dependent entropy deficit | DBZ7STJGZM | statement | record (an item of a paper that no node asks for yet. The record keeps its edges in the record plane (corpus arxiv AX8.6)) | arXiv 2609.38228#897H |
| One clock, not two | 200WD7K7FK | statement | record (an item of a paper that no node asks for yet. The record keeps its edges in the record plane (corpus arxiv AX8.6)) | arXiv 2609.27908#YPU2 |
| One colouring pass | KJBRB85EQM | statement | record (an item of a paper that no node asks for yet. The record keeps its edges in the record plane (corpus arxiv AX8.6)) | arXiv 2609.28160#3KH5 |
| One common period for the next layer | 8T8N78KMNN | statement | record (an item of a paper that no node asks for yet. The record keeps its edges in the record plane (corpus arxiv AX8.6)) | arXiv 2610.06925#BBVU |
| One conditional \evar | KPTFQ6FK4H | statement | record (an item of a paper that no node asks for yet. The record keeps its edges in the record plane (corpus arxiv AX8.6)) | arXiv 2609.27766#BWML |
| One contraction retaining large corank | S9PT4GZTYF | statement | record (an item of a paper that no node asks for yet. The record keeps its edges in the record plane (corpus arxiv AX8.6)) | arXiv 2610.20649#YUKU |