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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 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 internal-categories k-theory lie-theory limits linear linear-algebra locale localization logic mathematics measure 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 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.
   • CommentAuthorJohn Baez
   • CommentTimeAug 9th 2019
   • PermaLink
   Author: John Baez
   Format: MarkdownItexFixed third definition of 3-group. <a href="https://ncatlab.org/nlab/revision/diff/3-group/6">diff</a>, <a href="https://ncatlab.org/nlab/revision/3-group/6">v6</a>, <a href="https://ncatlab.org/nlab/show/3-group">current</a>

   Fixed third definition of 3-group.

   diff, v6, current

2. • CommentRowNumber2.
   • CommentAuthorAli Caglayan
   • CommentTimeAug 9th 2019
   • PermaLink
   Author: Ali Caglayan
   Format: MarkdownItexWhat does it mean for a 1-morphism to have a weak inverese? Is it some morphism that tensors to the identity?

   What does it mean for a 1-morphism to have a weak inverese? Is it some morphism that tensors to the identity?

3. • CommentRowNumber3.
   • CommentAuthorRichard Williamson
   • CommentTimeAug 9th 2019
   • (edited Aug 9th 2019)
   • PermaLink
   Author: Richard Williamson
   Format: MarkdownItexShould just mean that it is an isomorphism up to a 2-isomorphism (and maybe some coherence conditions).

   Should just mean that it is an isomorphism up to a 2-isomorphism (and maybe some coherence conditions).