Not signed in

Want to take part in these discussions? Sign in if you have an account, or apply for one below

• Username
• Password
• Remember me

• Sign in using OpenID
• Remember me

• Forgot your password?
• Apply for membership

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.
   • CommentAuthorEric
   • CommentTimeOct 25th 2009
   • PermaLink
   Author: Eric
   Format: MarkdownI weakened the definition of [[covering relation]] for directed graphs so that <latex>(x,y)</latex> satisfy the covering relation if their is an edge <latex>x\to y</latex> and no other path from <latex>x</latex> to <latex>y</latex>. The condition that there is no <latex>z</latex> with edges <latex>x\to z</latex> and <latex>z\to y</latex> is too strong.

   I weakened the definition of covering relation for directed graphs so that satisfy the covering relation if their is an edge and no other path from to . The condition that there is no with edges and is too strong.

2. • CommentRowNumber2.
   • CommentAuthorTobyBartels
   • CommentTimeOct 25th 2009
   • PermaLink
   Author: TobyBartels
   Format: MarkdownYou mean too weak? Yes, that sounds quite reasonable, even before considering whether it gives us the right definition of [[Hasse diagram]].

   You mean too weak? Yes, that sounds quite reasonable, even before considering whether it gives us the right definition of Hasse diagram.