| János Körner | 6CPCX54D0T | topic | open | Wikipedia János Körner, Wikidata Q15822188 |
| János Pach | CAJ7XFC0TV | topic | open | Wikipedia János Pach, Wikidata Q10561955 |
| János Pach | CHQXSCB7XM | topic | open | Wikipedia List of people by Erdős number#5I8F, Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#ZQO1 |
| János Pach | Z6TC2NH7R6 | topic | open | Wikipedia List of books in computational geometry#JQS2 |
| János Pintz | 442ANAXZJJ | topic | open | Wikipedia List of people by Erdős number#CH5F, Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#H1O4 |
| János Pintz | HP7ZS1S2CS | topic | open | Wikipedia János Pintz, Wikidata Q963230 |
| Jérôme Franel | YT688HP1MX | topic | open | Wikipedia Jérôme Franel, Wikidata Q3190903 |
| Jñanasrimitra | NFB4AJFKFQ | unknown | open | Wikipedia List of logicians#RPRX |
| Jónsson | MZN0XPZGCN | definition | open | Wikipedia Glossary of set theory#F05G |
| Jónsson algebra | VWSBHJ7M7A | definition | open | Wikipedia List of unsolved problems in mathematics#DTKZ |
| Jónsson cardinal | 2BB6W3M2RX | definition | open | Wikipedia Jónsson cardinal, Wikidata Q6320393 |
| Jónsson function | 4D3BQKKE03 | definition | open | Wikipedia Jónsson function, Wikidata Q6320395 |
| Jónsson term | H7580NGYHD | definition | open | Wikipedia Jónsson term, Wikidata Q48996249 |
| Jónsson's lemma | Q4R4A54J3Z | definition | open | Wikipedia List of lemmas#BOP0 |
| Jónsson–Tarski algebra | JG342AJ533 | definition | deferred (the item has its own article, page 43193940) | Wikipedia List of things named after Alfred Tarski#0DP3 |
| Jónsson–Tarski algebra | YYWMFH65PB | definition | open | Wikipedia Jónsson–Tarski algebra, Wikidata Q18208351 |
| Jónsson–Tarski duality | 2Q85SYGWNQ | unknown | open | Wikipedia General frame#Q1D2 |
| Jónsson–Tarski duality | YY5PKCE44A | definition | deferred (the item has its own article, page 6933049) | Wikipedia List of things named after Alfred Tarski#2BST, Wikipedia List of dualities#H235 |
| Józef Emanuel Jankowski | 5204DR6660 | topic | open | Wikipedia Józef Emanuel Jankowski, Wikidata Q15135901 |
| Józef Maria Bocheński | 57AYC4AXBT | topic | open | Wikipedia List of logicians#FFNI |
| Józef Maria Bocheński | FDEPDBRTS0 | topic | open | Wikipedia Józef Maria Bocheński, Wikidata Q673672 |
| Józef Maria Hoene-Wroński | 3JJPSNT6K3 | topic | deferred (the item has the flag informal (WP9.2)) | Wikipedia Józef Maria Hoene-Wroński, Wikidata Q331856 |
| Józef Schreier | 4QRANCC7TV | topic | deferred (the item has the flag informal (WP9.2)) | Wikipedia Józef Schreier, Wikidata Q10308559 |
| Józef Schreier | TQV7AM245W | topic | open | Wikipedia List of Jewish mathematicians#6NVN |
| József Balogh | 9VRC8W612S | topic | open | Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#69R4 |
| József Balogh | S454KKJQDB | topic | open | Wikipedia József Balogh (mathematician), Wikidata Q30541324 |
| József Beck | FDGQV87XFN | unknown | open | Wikipedia List of people by Erdős number#A4PM, Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#7T8X |
| József Kürschák | D948J4MR5S | topic | open | Wikipedia List of sums of reciprocals#49KJ |
| József Kürschák | FNTASA6QAT | topic | open | Wikipedia József Kürschák, Wikidata Q182967 |
| József Kürschák | SSM8DPG8H7 | topic | open | Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#N53C |
| József Solymosi | BTMJBS2H65 | unknown | open | Wikipedia List of people by Erdős number#L4IE |
| Jöreskog, Karl Gustav | 2NTXDF6ACY | topic | open | Wikipedia List of statisticians#THEY |
| Jörg Bewersdorff | ZB4JM4MVWJ | topic | open | Wikipedia Jörg Bewersdorff, Wikidata Q89025 |
| Jörg Teschner | 24RNC6P2G4 | unknown | open | Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#5JCD |
| Jörg-Rüdiger Sack | 3HN04MB66T | unknown | open | Wikipedia List of people by Erdős number#DWZW |
| Jörn Dunkel | JRB11TDRJS | topic | open | Wikipedia Jörn Dunkel, Wikidata Q42323437 |
| Jørg Tofte Jebsen | 3W7EKK5J52 | unknown | open | Wikipedia List of contributors to general relativity#U75Z |
| Jørgen Dybvad | H5TMMRR8MC | topic | open | Wikipedia Jørgen Dybvad, Wikidata Q6321467 |
| Jørgen Pedersen Gram | X70B9SBRKK | topic | out_of_scope (a person, not an item of mathematics) | Wikidata Q957238, ProofWiki Mathematician:Jørgen_Pedersen_Gram, Wikipedia Jørgen Pedersen Gram |
| Jørgensen's dilemma | 69AXZ9VZT7 | unknown | open | Wikipedia Imperative logic#CFPS |
| Jørgensen's inequality | 64WDBDC740 | statement | deferred (the item has the flag informal (WP9.2)) | Wikipedia Jørgensen's inequality, Wikidata Q6321608 |
| Júlia Volaufová | 1Q9P01RGGW | topic | open | Wikipedia List of fellows of the American Statistical Association#8P6C |
| Júlia Volaufová | TEYN3M2P95 | topic | open | Wikipedia Júlia Volaufová, Wikidata Q102343917 |
| Júlio César de Mello e Souza | VDTSZ7MPJ4 | topic | out_of_scope (a person, not an item of mathematics) | Wikidata Q2520014, ProofWiki Mathematician:Júlio_César_de_Mello_e_Souza, Wikipedia Júlio César de Mello e Souza |
| Jürg Fröhlich | P18J70QJPM | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q122729, nLab Jürg Fröhlich |
| Jürg Fröhlich | RCZBN6QD7Y | unknown | open | Wikipedia List of people by Erdős number#69EY, Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#2AH6, Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#9VFP, Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#XBQU |
| Jürg Peter Buser | F18BBGSRWW | topic | open | Wikipedia Jürg Peter Buser, Wikidata Q1464582 |
| Jürgen Ehlers | 1FTP481KHW | unknown | open | Wikipedia List of contributors to general relativity#T2DK |
| Jürgen Fuchs | YHP0YR8XCB | unknown | out_of_scope (a person, not an item of mathematics) | Wikidata Q1717177, nLab Jürgen Fuchs |
| Jürgen Gärtner | H7JXH391S8 | topic | open | Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#HNHT |
| Jürgen Gärtner | PWKPR99Z47 | topic | open | Wikipedia Jürgen Gärtner, Wikidata Q30555488 |
| Jürgen Herzog | 6J0X7FPBSX | topic | open | Wikipedia Jürgen Herzog, Wikidata Q79052321 |
| Jürgen Jost | 9B917Z7P1X | topic | out_of_scope (a person, not an item of mathematics) | Wikidata Q108439, nLab Jürgen Jost, Wikipedia Jürgen Jost |
| Jürgen Jost | TTBNK55DVC | topic | open | Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#MNZF, Wikipedia List of German mathematicians#65NX |
| Jürgen Mittelstraß | HEY8PDA24J | topic | open | Wikipedia Jürgen Mittelstraß, Wikidata Q95189 |
| Jürgen Moser | 6RANZ0M68N | topic | open | Wikipedia List of people by Erdős number#XL1J, Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#0X4V, Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#X5AH, Wikipedia List of International Congresses of Mathematicians Plenary and Invited Speakers#ZF23, Wikipedia List of German mathematicians#9OMK |
| Jürgen Moser | XKQ092ACK8 | topic | out_of_scope (a person, not an item of mathematics) | Wikidata Q65209, nLab Jürgen Moser, Wikipedia Jürgen Moser |
| Jürgen Neukirch | E31ZPECFD4 | topic | out_of_scope (a person, not an item of mathematics) | Wikidata Q85514, nLab Jürgen Neukirch, Wikipedia Jürgen Neukirch |
| Jürgen Neukirch | RN40WM5K9P | topic | open | Wikipedia List of German mathematicians#7GQA |
| Jürgen Pilz | XFPS7D66VC | topic | open | Wikipedia Jürgen Pilz, Wikidata Q84118683 |