nLab Author — Todd Trimble

Overview

Todd Trimble has contributed to 1313 nLab pages.

Most recent contributions

All pages contributed to

• (bo, ff) factorization system
• (classical) axiom of multiple choice
• (infinity,n)-module
• (n,1)-topos
• (n,r)-category
• 0-category
• 2-category
• 2-topos
• 2-vector space
• 2009 August changes
• 2009 July changes
• 2009 June changes
• 2009 September changes
• 3-manifold
• 7-sphere
• Ab-enriched category
• abc conjecture
• abelian category
• abelianization
• About
• absorption category
• abstract elementary class
• abstraction
• accessible topological space
• action
• additive category
• adic noetherian ring
• adinkra
• adjoint functor
• adjoint functor theorem
• adjoint string
• adjunct
• adjunction
• affine logic
• affine space
• affine variety
• Alex Hoffnung
• Alfred Gray
• algebra for an endofunctor
• algebra over a monad
• algebra over an operad
• algebrad
• algebraic definition of higher categories
• algebraic geometry
• algebraic integer
• algebraic K-theory
• algebraic lattice
• algebraic number
• algebraic theory
• algebraic variety
• algebraically closed field
• all arrows monic > history
• allegory
• almost connected topological group
• alternating group
• alternative algebra
• amazing right adjoint
• amnestic functor
• anafunctor
• analysis
• André Joyal
• Anthony Elmendorf
• antichain
• Anton Geraschenko
• apartness relation
• approximate integral domain
• approximation of the identity
• arccos
• archimedean group
• arctangent
• arithmetic
• Artin gluing
• assignment > history
• associahedron
• AT category
• Atiyah Lie groupoid
• atom
• atom (disambiguation)
• atomic category
• augmented simplicial set
• automorphic form
• automorphism of the complex numbers
• axiom
• axiom of choice
• axiom of multiple choice
• axiom of replacement
• Baer's criterion
• Baire space
• Baire space of sequences
• balanced category
• ball
• Banach algebra
• Banach space
• bar construction
• baryon-lepton symmetry
• base
• base of enrichment
• basic complex line bundle on the 2-sphere
• basics of etale cohomology
• basis in functional analysis
• basis theorem
• Batanin omega-category
• beable
• Bernard Bolzano
• Bernhard Banaschewski
• Bernoulli number
• BGG resolution
• BHK interpretation
• bi-pointed object
• bicategory
• bicategory of relations
• bicommutant theorem
• bicomodule
• bifunctor
• bijective proof
• bilinear form
• bimodule
• bimorphism > history
• binary Golay code
• binary linear code
• binomial theorem
• bipartite graph
• biproduct
• biring
• black hole
• Bohr compactification
• BoolAlg
• Boolean algebra
• Boolean locale
• Boolean ring
• Boolean topos
• bornological set
• bound state
• boundary
• Bourbaki
• braid category
• braid group
• branched cover of the Riemann sphere
• Brown representability theorem
• bump function
• Burnside ring
• C^∞-ring
• calculus
• cancellative element of a commutative ring
• canonical bundle
• canonical form
• canonical model structure on Cat
• Cantor space
• Cantor's theorem
• Cantor-Schroeder-Bernstein theorem
• cardinal arithmetic
• cardinal number
• cartesian bicategory
• cartesian closed category
• cartesian monad
• cartesian natural transformation
• cartesian product
• cartesian space
• Catalan number
• categorical semantics of dependent type theory
• Categories for the Working Mathematician
• Categories, Allegories
• category
• category enriched in a bicategory
• category of cubes
• category of fractions
• category of presheaves
• category of sheaves
• category of simple graphs
• category of simple graphs and some graph theory
• category theory
• category with class structure
• category with duals
• Cauchy complete category
• Cauchy group theorem
• Cayley-Dickson construction
• celestial sphere
• cellular approximation theorem
• cellular homology
• chain rule
• characteristic polynomial
• Charles Sanders Peirce
• Chern character
• Chevalley-Eilenberg algebra
• child's drawing
• Chu construction
• Chu–Vandermonde identity
• class equation
• class function (set theory)
• classical logic
• classical mathematics
• classical r-matrix
• classifying topos
• classifying topos for the theory of objects
• clique
• closed category
• closed functor
• closed intervals are compact topological spaces
• closed midpoint algebra
• closed monoidal category
• closed monoidal structure on presheaves
• closed subspace
• closed-projection characterization of compactness
• closure operator
• club
• co-Yoneda lemma
• coalgebra
• coalgebra for an endofunctor
• coalgebra of the real interval
• coarse structure
• cobordisms as presheaves > history
• cocategory
• CocommCoalg
• cocommutative coalgebra
• cocompleteness of varieties of algebras
• code loop
• codensity monad
• codiagonal
• codiscrete groupoid
• coequalizer
• cofinite topology
• cofree coalgebra
• cogenerator
• cograph of a functor
• cogroup
• Cohen-Macaulay module
• coherence and strictification for monoidal categories
• coherence law
• coherence theorem
• coherent sheaf
• coimage
• coinduction
• Cole's theory of spectrum
• colimit
• colimits in categories of algebras
• colimits of normal spaces
• colimits of paracompact Hausdorff spaces
• colored symmetric sequence
• commutant
• commutative algebraic theory
• commutative monoidal category
• comonadic functor
• compact element
• compact Hausdorff rings are profinite
• compact Hausdorff spaces are normal
• compact object
• compact space
• compactification
• compactly generated topological space
• compactness and stable closure
• compactness theorem
• compactum
• complement
• complete augmented algebra
• complete Boolean algebra
• complete space
• completely distributive lattice
• completion
• complex manifold
• complex number
• composition algebra
• computable function (analysis)
• computable function > history
• computad
• concrete category
• concrete sheaf
• condensed set
• cone
• confluent category
• conic section
• connected limit
• connected object
• connected space
• connectology
• conservative functor
• constant functor
• constant of a theory
• constant polynomial
• constructive mathematics
• continuation monad
• continued fraction
• continuous functor
• continuous poset
• continuum
• continuum hypothesis
• convenient category of topological spaces
• convergence space
• convex function
• convex set
• copower
• coproduct-preserving representable
• coprojection
• Coq
• core of a ring
• coreader comonad
• coreflective subcategory
• cosmological constant
• cosmos
• cotangent function
• cotopology
• countable chain condition
• countable ordinal
• countable set
• countable unions of countable sets are countable
• countably compact topological space
• counterexamples in algebra
• counterterm
• covering space
• Coxeter group
• Coyoneda lemma > history
• Crans-Gray tensor product
• cross ratio
• crossed module
• cubical set
• cubulation
• cumulative hierarchy
• currying
• cut rule
• CW complex
• CW-complexes are paracompact Hausdorff spaces
• cyclic category
• cyclic operad
• cyclic order
• cyclic permutation
• cyclic set
• cyclotomic field
• cylinder on a presheaf
• David Speyer
• Day convolution
• Day's reflection theorem
• De Morgan Heyting algebra
• decalage
• decidability
• Dedekind completion
• degree of a continuous function
• Dehn surgery
• Dehn twist
• Deligne tensor product of abelian categories
• delooping
• dense subcategory
• dense subspace
• dependent choice
• dependent sum
• derivation
• descriptive set theory
• determinant
• diagonal argument
• diagram
• diagram chasing lemmas - contents
• dichotomy between nice objects and nice categories
• differentiable map
• differential cohesive (infinity,1)-topos
• differentiation
• digraph
• dinatural transformation
• direct sum of Banach spaces
• directed graph
• discrete object
• discussion on terminology -- omega-category
• disjoint coproduct
• distribution
• distributive category
• distributive lattice
• distributive monoidal category
• distributivity of limits over colimits
• divisible group
• Dmitry Vladimirovich Alekseevsky
• doctrinal adjunction
• domain
• domain theory
• dominant functor
• Doplicher-Roberts reconstruction theorem
• double factorial
• double negation
• double negation translation
• double-negation topology > history
• Dowker's theorem
• dual
• dual adjunction
• dual object in a closed category
• dual vector space
• duality
• dualizable object
• dualizing object
• dualizing object in a closed category
• duoidal category
• e
• Eckmann-Hilton argument
• edge
• effective topos
• Einstein-Hilbert action
• elementary embedding
• elementary function
• elementary function arithmetic
• Elements
• elliptic curve
• embedding of categories
• empty 008
• empty 165
• empty 166
• empty 167
• empty set
• end
• end compactification
• endomorphism
• Engeler's lemma
• enriched category
• enriched functor
• enriched groupoid
• enriched monoidal category
• enriched natural transformation
• enriched Yoneda lemma
• epimorphism
• epimorphisms of groups are surjective
• epistemology
• equalizer
• equicontinuous family of functions
• equilogical space
• equivalence relation
• Errett Bishop
• error correcting code
• essential ideal
• essentially algebraic theory
• ETCC
• Euclid
• Euclidean domain
• Euclidean geometry
• Eudoxus real number
• Euler number
• Euler's formula
• even number
• eventual image
• exact category
• exact square
• excluded middle
• exclusive disjunction
• exotic smooth structure
• experimental alternative definition of functor
• experimental observation
• exponent of a group
• exponentiable functor
• exponential ideal
• exponential law for spaces
• exponential map
• exponential object
• extension
• extensional relation
• extensive category
• exterior
• extremal epimorphism
• extremum
• factorial
• factorization lemma
• falling factorial
• fan theorem
• Fermat quotient
• Fermat's little theorem
• field
• filler
• filter monad
• filtered category
• filtered colimit
• filtered object
• filtrality
• final functor
• finitary monad
• finite abelian category
• finite category
• finite field
• finite group
• finite topological space
• finite-dimensional vector space
• finitely complete category
• first uncountable ordinal
• first-order hyperdoctrine
• five lemma
• fixed point
• fixed-point combinator
• flag
• flat module
• focal point
• foliation
• folklore
• fork
• form
• formal group
• formal scheme
• frame
• framed link
• Fred Richman
• free abelian group
• free cartesian category
• free cocompletion
• free functor
• free module
• free monad
• free monoid
• free object
• free operad
• free topos
• freshman's dream
• Freyd cover
• Freyd-Mitchell embedding theorem
• Frobenius algebra
• Frobenius monad
• Frobenius reciprocity
• full and faithful functor
• fully formal ETCS
• fully normal spaces are equivalently paracompact
• Fulton-MacPherson operad
• funcoid
• function
• function extensionality
• functional relation
• functorially finite subcategory
• fundamental theorem of algebra
• fundamental theorem of calculus
• fundamental theorem of dg-algebraic rational homotopy theory
• fundamental theorem of finitely generated abelian groups
• funny tensor product
• fuzzy logic
• Gabriel and Zisman > history
• Galois connection
• Galois theory
• Gamma function
• Gamma-space
• Gelfand-Naimark-Segal construction
• General Discussion
• general linear group
• general relativity
• general topology
• generalized element
• generalized multicategory
• generalized scheme
• generic proof
• geometric definition of higher categories
• geometric morphism
• geometric realization
• geometric shape for higher structures
• geometric stability theory
• geometrodynamics
• geometry of physics
• Giry monad
• global element
• global field
• globe
• globular operad
• globular set
• golden ratio
• good open cover
• graded set
• Gram-Schmidt process
• graph
• graph minor
• graph theory > history
• graviphoton
• gravitational wave
• greatest common divisor
• Grothendieck category
• Grothendieck topos
• Grothendieck universe
• group
• group cohomology
• group extension
• group of ideles
• group of units
• groupoid
• Grp
• Haar integral
• Hadamard lemma
• Hahn series
• Hahn-Banach theorem
• Hans-Joachim Baues
• Harry Appelgate
• Hartogs number
• Haskell Curry
• Hausdorff implies sober
• Hausdorff maximal principle
• Hausdorff space
• Hawaiian earring space
• heap
• Hecke algebra
• Henselian ring
• hereditary property
• Hermite polynomial
• Heyting algebra
• higher category theory
• higher local field
• Hilbert cube
• Hilbert space
• Hilbert system
• Hilbert's basis theorem
• Hilbert's fifth problem
• Hilbert's Theorem 90
• historical notes on quasigroups
• Hochschild-Kostant-Rosenberg theorem
• hom-functor
• HomePage
• homogeneous polynomial
• homotopy coherent nerve
• homotopy type theory
• Hopf monad
• Hopf monoid
• Hopfian group
• horn
• Horn theory
• Horst Herrlich
• HowTo
• Hurwitz theorem
• hyperbolic 3-space
• hyperbolic curves
• hyperbolic function
• hyperbolic link
• hyperdeterminant
• hypermonoid
• hypothèse inspiratrice
• Hölder's inequality
• icosahedral group
• ideal
• ideal in a monoid
• idempotent monad
• idempotent semiring
• identity component
• identity element
• identity morphism
• identity-on-objects functor
• ILH manifold
• image
• implicative structure
• inaccessible cardinal
• incompleteness theorem
• independent family of sets
• induction
• inductive limit
• inductive type
• inhabited set
• initial algebra of an endofunctor
• initial object
• Initiality Project - Participants
• Initiality Project - Type Theory - Pi-types
• injective envelope
• injective module
• injective object
• inner product of multisets
• inner product space
• integer
• integrable distribution of subspaces
• integral domain
• integral lattice
• inter-universal Teichmüller theory
• interactions of images and pre-images with unions and intersections
• interior
• interior point
• internal category
• internal logic
• internally projective object
• interval
• interval object
• Introduction to Homotopy Theory
• inverse semigroup
• inverse trigonometric function
• irrational number
• irreducible element
• irreducible polynomial
• Isbell duality
• isometry
• iterated monoidal category
• Jacob Lurie
• James construction
• Jim Stasheff
• Jiří Adámek
• Jiří Rosický
• Joel Robbin
• John Isbell
• John L. Kelley
• John McKay
• Johnstone's topological topos
• join
• join of topological spaces
• Jon Beck
• José Meseguer
• Joyal delta-ring
• judgment
• Julian Rachman
• Julian Rachman > history
• k-morphism
• K-theory of a permutative category
• k-tuply monoidal n-category
• K3 surface
• Kan complex
• Kan extension
• Kan lift
• Kan-Thurston theorem
• Karoubi envelope
• Karoubian category
• Kazimierz Kuratowski
• Kelly-Mac Lane graph
• Kleene's second algebra
• Kleisli category
• Kleisli category of a comonad
• Kochen-Specker theorem
• Kolmogorov product
• Kolmogorov topological space
• Kuiper's theorem
• Kuratowski pairs
• König's theorem
• Lagrange multiplier
• lambda-calculus
• Lambda-ring
• Lambert W-function
• Latin square
• lattice
• lattice (discrete subgroup)
• lattice (in a vector space, etc.) > history
• Laurent series
• Lawvere theory
• lawvere theory > history
• Lawvere's fixed point theorem
• Lawvere-Tierney topology
• lax natural transformation
• lax-idempotent 2-monad
• Lazard ring
• Lebesgue space
• left cancellative category > history
• Leonhard Euler
• Leopoldo Nachbin
• lexicographic order
• Lie group
• Lie's three theorems
• lifted limit
• light
• limit
• limit point
• limit point compact space
• limits and colimits by example
• linear extension of a partial order
• linear hyperdoctrine
• linear logic
• linear type theory
• linearly distributive category
• linearly independent subset
• list of notable initial algebras and terminal coalgebras
• little cubes operad
• local field
• local geometric morphism
• local ring
• local section
• locale
• localic topos
• locally bounded category
• locally cartesian closed (infinity,1)-category
• locally cartesian closed category
• locally closed set
• locally compact and sigma-compact spaces are paracompact
• locally compact topological group
• locally compact topological space
• locally connected topos
• locally convex topological vector space
• locally finitely presentable category
• locally n-connected (n+1,1)-topos
• locally path-connected space
• locally presentable category
• locally ringed topos
• logarithm
• long line
• loop space
• Löwenheim-Skolem theorem
• M-category
• Malcev variety
• manifold
• mapping class group
• Markov category
• Maschke's theorem
• math blogs
• Mathieu moonshine
• matroid
• Max Kelly
• maximal compact subgroup
• maximal ideal
• maximal ideal theorem
• maximal torus
• Maxwell's equations
• maybe monad
• Mazur-Ulam theorem
• measurable cardinal
• measurable space
• measuring coalgebra
• meet
• metric space
• metric spaces are fully normal
• metrization theorem
• Michael Boardman
• Michael's theorem
• Mike Shulman
• Milnor slide trick
• Minkowski's inequality
• Mochizuki's proof of abc
• model
• model structure on dg-algebras
• model structure on relative categories
• model structure on simplicial presheaves
• model theory
• modification
• modified Bernoulli number
• modular curve
• modular lattice
• module
• module over a monad
• modules over a ring are equivalent to quasicoherent sheaves over its spectrum
• Moebius transformation
• monadic adjunction
• monadic functor
• monadicity theorem
• monoid
• monoidal adjunction
• monoidal category
• monoidal category with diagonals
• monoidal monad
• monoidal topos
• monoidally cocomplete category
• monomial matrix
• monomorphism
• Monster group
• Montague semantics
• Moore closure
• Moufang loop
• multicategory
• multifunctor
• multiplicative group of integers modulo n
• multiset
• MV algebras
• Myles Tierney
• mysticism
• Nakayama's lemma
• natural bundle
• natural numbers object
• natural transformation
• neighborhood base
• nerve
• net
• nice category of spaces
• nice topological space
• Nielsen-Schreier theorem
• nilpotent group
• nilradical
• noetherian ring
• non-unital operad
• noncommutative geometry
• norm
• normal space
• normal subgroup
• normed group
• nPOV
• nucleosynthesis
• null subset
• Nullstellensatz
• number
• number field
• nyan-cat > history
• o-minimal structure
• Omega-spectrum
• one-point compactification
• open cover
• open morphism
• operad
• operation
• order category > history
• order of a group
• order topology
• ordered field
• ordered group
• ordered pair
• ordinal sum
• ordinary differential equation
• oriental
• oriented graph
• orthogonal basis
• orthogonal subcategory problem
• orthogonality
• over-topos
• p-adic integer
• p-adic number
• p-derivation
• p-divisible group
• p-primary group
• paracompact Hausdorff spaces equivalently admit subordinate partitions of unity
• paracompact topological space
• parallelogram identity
• parametric right adjoint
• parity complex
• partial combinatory algebra
• partial function
• partial recursive function
• partial section
• pasting diagram
• pasting scheme
• Paul Hertz
• PBW theorem
• Peano arithmetic
• Peano curve
• Peirce > history
• perfect field
• perfect group
• perfect space
• periodic table of chemical elements
• permutation
• permutation matrix
• permutation representation
• perplex number
• Peter Freyd
• pi
• planar graph
• Planck's constant
• plasma
• Poincaré conjecture
• Poincaré group
• Poincaré sphere
• point of a topos
• pointed endofunctor
• pointed module
• pointed object
• pointed object in a monoidal category
• Poisson summation formula
• Polish space
• polynomial
• polynomial monad
• Pontrjagin dual
• Pontryagin duality > history
• Pos
• poset of subobjects
• power series
• pre-net
• precursors
• predicative mathematics
• predicative topos
• predual
• preimage
• PreOrd
• Preord > history
• preorder
• presentation axiom
• presheaf
• prime ideal theorem
• prime number theorem
• primitive element
• primitive recursive arithmetic
• principal ideal domain
• principal symbol
• PRO
• product formula for the sine function
• product law
• product-preserving functor
• profinite completion of a group
• profinite group
• profunctor
• projective line
• projective object
• projective resolution
• projective set
• prometric space
• proof
• proof by contradiction
• proof net
• proof of the prime number theorem
• PROP
• propositional theory
• Prüfer group
• pseudo-Riemannian metric
• pseudofunctor
• pseudotopological space
• Puiseux series
• Pursuing Stacks
• pushout
• pushout-product
• Pythagorean theorem
• Pythagorean triple
• Q/Z
• quadratic algebra
• quadratic reciprocity law
• quantale
• quantaloid
• quantification
• quantum channel
• quantum gravity
• quantum information theory via dagger-compact categories
• quantum logic
• quark-gluon plasma
• quasi-category
• quasi-topological space
• quasigroup
• quasitopos
• quaternion
• Quillen-Suslin theorem
• Quiv
• quotient object
• quotient space
• rack
• radical
• rational function
• rational homotopy theory
• real closed field
• real number
• realizability topos
• recollement
• recursive subset
• red herring principle
• redirect
• reductive group
• reflective subcategory
• reflexive coequalizer
• reflexive graph
• regular and exact completions
• regular cardinal
• regular category
• regular element
• regular epi > history
• regular epimorphism
• regular homotopy
• regular monomorphism
• regular space
• Rel
• relational beta-module
• relative adjoint functor
• relative category
• representable > history
• representable functor
• representable functor theorem
• restriction of scalars
• retract
• RHIC
• ribbon graph
• Richard J. Wood
• Riemann surface via valuations
• Riesz space
• rig
• rigged Hilbert space
• rigid monoidal category
• rigid object
• ring
• ring object
• ring of adeles
• ring of integers
• ring over a ring
• Robinson arithmetic
• Roger Godement
• Roger Penrose
• root
• root of unity
• Rudolf Fritsch
• Russell's paradox
• Ryszard Engelking
• Saharon Shelah
• Sakura Schäfer-Nameki
• salamander lemma
• Sanath Devalapurkar
• Sandbox
• Schanuel's conjecture
• scheme
• Schur functor
• Schwartz space
• Schwartz-Bruhat function
• Scott's trick
• second-countable space
• second-order arithmetic
• Segal's category
• self-distributive operation
• semi-locally simply-connected topological space
• semialgebraic set
• semicartesian monoidal category
• semicategory
• semigroup
• sentence
• separable algebra
• separable functor
• separable space
• separated presheaf
• separation axioms
• sequence
• sequential spectrum
• sequential topological space
• sequentially compact topological space
• Serre's criterion of affineness
• Serre-Swan theorem
• sesquicategory
• Set
• set theory
• several complex variables
• Sheaves in Geometry and Logic
• Shelah's main gap
• shelf
• short map
• sieve
• sifted colimit
• sigma-algebra
• signature
• signature (in logic)
• signature of a permutation
• signed graph
• simple group
• simple object
• simple ring
• simple root
• simplex
• simplex category
• simplicial approximation theorem
• simplicial complex
• simplicial principal bundle
• simplicial set
• simplicially enriched category
• simulation
• sine
• site
• slope of a line
• small category
• smash product
• smooth manifold
• smooth map
• smooth topos
• sober topological space
• sol > history
• Some Thoughts on the Future of Category Theory
• Sorgenfrey line
• span trace
• special Lagrangian submanifold
• specialization order
• specialization topology
• spectral sequence
• spectral theorem
• split exact sequence
• split idempotent
• splitting field
• splitting principle
• square root
• stability in model theory
• stable (infinity,1)-category
• stack
• star domain
• star-autonomous category
• state on a star-algebra
• Stephan Wannowski
• Stephen Britton
• Stephen Schanuel
• stereographic projection
• stereotype space
• Steve Vickers
• Steven Duplij
• Stiefel manifold
• Stiefel-Whitney class
• Stigler's law of eponymy
• Stirling's approximation
• Stone duality
• Stone-Weierstrass theorem
• Stone-Čech compactification
• strict 2-category
• string theory FAQ
• structure
• structure (model theory)
• structure in model theory
• structure theorem for finitely generated modules over a principal ideal domain
• subdivision
• subobject
• subobject classifier
• subsequential space
• subspace topology
• subterminal object
• super vector space
• supermanifold
• SupLat
• suplattice
• Suren Arakelov
• surreal number
• Sylow p-subgroup
• symmetric group
• symmetric sequence
• symplectomorphism
• synthetic geometry
• synthetic homotopy theory
• syntopogenous space
• Tall-Wraith monoid
• tangent bundle
• tangent function
• Tannaka duality
• Tarski group
• Tarski-Seidenberg theorem
• taut functor
• Taylor Dupuy
• tensor category
• tensor product of Banach spaces
• tensor product of enriched categories
• Terence Tao
• terminal coalgebra for an endofunctor
• terminal geometric morphism
• terminal object
• tetracategory
• The QED Project
• The Rising Sea
• theory
• theory of algebraically closed fields
• Theta category
• Thom space
• Thom's theorem
• tileorder
• Timeline of category theory and related mathematics
• tiny object
• Todd Trimble
• Top
• topological concrete category
• topological field
• topological group
• topological interval
• topological invariance of dimension
• topological ring
• topological space
• topological vector bundle
• topological vector space
• topology
• topology -- references
• topos
• topos of coalgebras over a comonad
• torsion subgroup
• torsor
• total category
• total relation
• totally disconnected space
• totally distributive category
• trace of a category
• transcendence degree
• transfor
• tree
• triality
• triangulated category
• triangulation
• trigonometric function
• trigonometric identity
• Trimble n-category
• Trimble on ETCS I
• Trimble on ETCS III
• Trimble rewiring
• Trimble's notion of weak n-category > history
• tripos
• trivial group
• tube lemma
• tubular neighborhood theorem
• twistor space
• two-sided bar construction
• Tychonoff space
• Tychonoff theorem
• Tychonoff theorem for locales
• types and logic - table
• ultrafilter
• ultrafilter theorem
• ultrapower
• ultraproduct
• unbounded operator
• under category
• underlying topological space
• Understanding M-Set
• uniform space
• unique factorization domain
• unitary group
• unitary matrix
• unitary representation of the Poincaré group
• universal algebra in a monoidal category
• universal element
• universal quantifier
• universe
• unnatural isomorphism
• Urysohn metrization theorem
• Urysohn's lemma
• valuation ring
• Vandermonde determinant
• vanishing at infinity
• vector bundle
• vector space
• Victor Porton
• Vietoris complex
• Vladimir Voevodsky
• volume conjecture
• von Neumann algebra
• von Neumann regular ring
• Věra Trnková
• walking structure
• Warsaw circle
• weak excluded middle
• weak omega-category
• weakly Hausdorff topological space
• Weierstrass elliptic function
• weighted colimit
• well-founded coalgebra
• well-founded relation
• well-order
• well-ordering theorem
• well-pointed topos
• well-powered category
• well-quasi-order
• wide pullback
• William Lawvere
• William T. Tutte
• William Thurston
• writing in the nLab
• Yoneda lemma
• Yoneda reduction
• Young diagram
• Young's inequality
• Yuri Manin
• Zariski site
• zero locus
• ZFC
• zigzag category
• Zorn's lemma
• étale space
• étale topos
• étendue