name,objects_hr,arrows_hr Mat_k,the natural numbers,matrices over fields k Mat_R,the natural numbers,matrices over rings R Mat_SR,the natural numbers,matrices over semirings SR Meas,measurable spaces,measurable maps Mod(Ab),modules of monoids in Ab (rings),module maps CMon,commutative monoids,monoid maps Mon,monoids,monoid maps Pos,partial orders,monotone maps PreOrd,preorders,monotone maps Pros,preorders,monotone maps Δ,the inhabited simplices,monotone maps Operad,symmetric multicategories,multifunctors PermCat,permutative (symmetric strict monoidal) categories,multilinear functors MultiSet,multisets,multimaps nCob,(n-1)-dimensional compact oriented manifolds,n-dimensional cobordisms Ho(Cat),categories,natural isomorphism classes of functors Ho(Grpd),groupoids,natural isomorphism classes of functors Species,species,natural transformations Cluster,partitioned sets,non-refinement-increasing maps Rng,nonunital rings,nonunital ring maps FinOrd,the finite ordinal numbers,order-preserving maps Pfn,sets,partial maps RT(K₁),the natural numbers,partial realizable maps RT(K₂),sequences of natural numbers,partial realizable maps Perm,the natural numbers,permutations PDiff,piecewise-differentiable manifolds,piecewise-continuous maps PL,piecewise-linear manifolds,piecewise-continuous maps Prof,categories,profunctors BiCat,bicategories,pseudofunctors Rel,sets,relations AdmRep,admissible domain representations,representable continuous maps AbCat,Abelian categories,right exact functors Rex,finitely cocomplete categories,right exact functors CRing,commutative rings,ring maps Ring,rings,ring maps SRing,simplicial rings,ring maps SemiGrp,semigroups,semigroup maps SemiLat,semilattices,semilattice maps SemiRing,semirings (rigs),semiring maps BanRing,Banach rings,short group maps CompNormGrp,complete normed groups,short group maps NormGrp,normed groups,short group maps NormRing,normed (commutative) rings,short group maps BanAlg,Banach algebras,short linear maps Ban_k,Banach spaces over fields k,short linear maps FinHilb,finite-dimensional Hilbert spaces,short linear maps Hilb,Hilbert spaces,short linear maps CompMet,complete metric spaces,short maps FinMet,finite metric spaces,short maps LMet,Lawvere metric spaces,short maps Met,metric spaces,short maps PseudoMet,pseudometric spaces,short maps SymLMet,symmetric Lawvere metric spaces,short maps SSet,simplicial sets,simplicial maps SimpCat,simplicially enriched categories,simplicially enriched functors Aut,regular (Moore) automata,simulations LieGrp,Lie groups,smooth group maps CartSp,Cartesian spaces,smooth maps Man,smooth manifolds,smooth maps SMan,simplicial smooth manifolds,smooth maps Span(Set),sets,spans of functions Span(Grpd),groupoids,spans of tame functors Spectra,topological spectra,spectrum maps SupLieAlg_k,Lie algebras over super vector spaces over fields k,super linear maps SupVect_k,super vector spaces over fields k,super linear maps Quant,quantales,suplattice maps SupLat,suplattices,suplattice maps Surj,sets,surjections SymmRel,sets,symmetric relations Feyn,Feynman diagrams,symmetries of Feynman diagrams 2,two objects,the walking arrow (and two identity arrows) I,two objects,the walking isomorphism (and two identity arrows) Ω,the inhabited trees,tree maps Hilb₀,Hilbert spaces,unitary operators DagCat,†-categories (dagger categories),†-functors (dagger functors)