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2-category 2-category-theory abelian-categories adjoint algebra algebraic algebraic-geometry algebraic-topology analysis analytic-geometry arithmetic arithmetic-geometry book bundles calculus categorical categories category category-theory chern-weil-theory cohesion cohesive-homotopy-type-theory cohomology colimits combinatorics complex complex-geometry computable-mathematics computer-science constructive cosmology deformation-theory descent diagrams differential differential-cohomology differential-equations differential-geometry digraphs duality elliptic-cohomology enriched fibration finite foundation foundations functional-analysis functor gauge-theory gebra geometric-quantization geometry graph graphs gravity grothendieck group group-theory harmonic-analysis higher higher-algebra higher-category-theory higher-differential-geometry higher-geometry higher-lie-theory higher-topos-theory homological homological-algebra homotopy homotopy-theory homotopy-type-theory index-theory integration integration-theory k-theory lie-theory limits linear linear-algebra locale localization logic mathematics measure-theory modal modal-logic model model-category-theory monad monads monoidal monoidal-category-theory morphism motives motivic-cohomology nlab noncommutative noncommutative-geometry number-theory of operads operator operator-algebra order-theory pages pasting philosophy physics pro-object probability probability-theory quantization quantum quantum-field quantum-field-theory quantum-mechanics quantum-physics quantum-theory question representation representation-theory riemannian-geometry scheme schemes set set-theory sheaf sheaves simplicial space spin-geometry stable-homotopy-theory stack string string-theory superalgebra supergeometry svg symplectic-geometry synthetic-differential-geometry terminology theory topology topos topos-theory tqft type type-theory universal variational-calculus

1. • CommentRowNumber1.
   • CommentAuthorUrs
   • CommentTimeNov 23rd 2011
   • PermaLink
   Author: Urs
   Format: MarkdownItexI have created a list [[discrete and concrete objects - contents]] to be used as a "floating TOC" and have included it into relevant entries. In this context I have also created [[concrete object]], [[co-concrete object]] and [[discrete object]] and [[codiscrete object]] redirect to the existing [[discrete space]] and [[codiscrete space]].

   I have created a list discrete and concrete objects - contents to be used as a “floating TOC” and have included it into relevant entries.

   In this context I have also created concrete object, co-concrete object and discrete object and codiscrete object redirect to the existing discrete space and codiscrete space.

2. • CommentRowNumber2.
   • CommentAuthorMike Shulman
   • CommentTimeJan 12th 2015
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   Author: Mike Shulman
   Format: MarkdownItexThe page [[co-concrete object]] doesn't appear to actually contain a definition of co-concrete objects.

   The page co-concrete object doesn’t appear to actually contain a definition of co-concrete objects.

3. • CommentRowNumber3.
   • CommentAuthorUrs
   • CommentTimeJan 12th 2015
   • PermaLink
   Author: Urs
   Format: MarkdownItexThanks for the alert. Hm, I forget what the definition was even supposed to be. Maybe objects $X$ for which $\flat X\to X$ is an epi? (Which is one kind of dual to the condition for concrete objects viz. $X \to \sharp X $ a mono.)

   Thanks for the alert. Hm, I forget what the definition was even supposed to be. Maybe objects $X$ for which $\flat X\to X$ is an epi? (Which is one kind of dual to the condition for concrete objects viz. $X \to \sharp X$ a mono.)

4. • CommentRowNumber4.
   • CommentAuthorMike Shulman
   • CommentTimeJan 12th 2015
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   Author: Mike Shulman
   Format: MarkdownItexThat was my guess upon encountering the term.

   That was my guess upon encountering the term.

5. • CommentRowNumber5.
   • CommentAuthorUrs
   • CommentTimeJan 13th 2015
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   Author: Urs
   Format: MarkdownItexOkay, I have edited the entry accordingly.

   Okay, I have edited the entry accordingly.