We prove that every injective simplicial map F(S) → F(S′) between flip graphs is induced by a subsurface inclusion S → S′, except in finitely many cases. This extends a result of Korkmaz–Papadopoulos which asserts that every automorphism of the flip graph of a surface without boundary is induced by a surface homeomorphism.

In this paper we study the notions of cogenerator and subdirectlyirreducible in the category of S-poset. First we give somenecessary and sufficient conditions for a cogenerator $S$-posets.Then we see that under some conditions, regular injectivityimplies generator and cogenerator. Recalling Birkhoff'sRepresentation Theorem for algebra, we study subdirectlyirreducible S-posets and give this theo...

In this article, we show that the Goldman–Iwahori metric on space of all norms a fixed vector satisfies Helly property for balls. On non-Archimedean side, deduce most classical Bruhat–Tits buildings may be endowed with natural piecewise ? ? $\ell ^\infty$ which is injective. We also prove semisimple groups over local fields act properly and cocompactly graphs. This gives another proof biautomat...

In this paper, we show that injectivity with respect to the class $mathcal{D}$  of dense monomorphisms of an idempotent and weakly hereditary closure operator of an arbitrary category  well-behaves. Indeed, if $mathcal{M}$ is a subclass of monomorphisms, $mathcal{M}cap mathcal{D}$-injectivity  well-behaves. We also introduce the notion of $(r,t)$-injectivity in the category {bf S-Act}, where $r...

Let Λ be an Artinian algebra and F an additive subbifunctor of ExtΛ(−,−) having enough projectives and injectives. We prove that the dualizing subvarieties of mod Λ closed under F -extensions have F -almost split sequences. Let T be an F -cotilting module in mod Λ and S a cotilting module over Γ = End(T ). Then Hom(−, T ) induces a duality between F -almost split sequences in ⊥F T and almost sp...

Given two graphs G = (VG, EG) and H = (VH , EH), a homomorphism from G to H is a function f : VG → VH such that for every uv ∈ EG, f(u)f(v) ∈ EH . A homomorphism from G to H is referred to as an H-colouring of G and the vertices of H are regarded as colours. The graph H is called the target of the homomorphism. These definitions extend to directed graphs by requiring that the mapping must prese...

Let M $M$ be a hyperbolic 3-manifold with no rank two cusps admitting an embedding in S 3 $\mathbb {S}^3$ . Then, if admits exhaustion by π 1 $\pi _1$ -injective sub-manifolds there exists Cantor sets C n ⊆ $C_n\subseteq \mathbb such that N = ∖ $N_n=\mathbb {S}^3\setminus C_n$ is and → $N_n\rightarrow M$ geometrically.