We study the problem how to draw a planar graph crossing-free such that every vertex is incident to an angle greater than π. In general a plane straight-line drawing cannot guarantee this property. We present algorithms which construct such drawings with either tangent-continuous biarcs or quadratic Bézier curves (parabolic arcs), even if the positions of the vertices are predefined by a given ...

In this paper, we study the duals of some finite dimensional pointed Hopf algebras working over an algebraically closed field k of characteristic 0. In particular, we study pointed Hopf algebras with coradical k[Γ] for Γ a finite abelian group, and with associated graded Hopf algebra of the form B(V )#k[Γ] where B(V ) is the Nichols algebra of V = ⊕iV χi gi ∈ k[Γ] k[Γ]YD. As a corollary to a ge...

Definition 1.2 The invariants of H in A is the set A of those a ∈ A, that ha = ε(h)a for each h ∈ H. Straightforvard computations shows, that A is the subalgebra of A. We refer reader to [5], [6] for the basic information concerning Hopf algebras and their actions on associative algebras. As a generalization of the well-known fact for group actions the following question raised in [5] ( Questio...

For set functors preserving intersections, a new description of the final coalgebra and the initial algebra is presented: the former consists of all well-pointed coalgebras. These are the pointed coalgebras having no proper subobject and no proper quotient. And the initial algebra consists of all well-pointed coalgebras that are well-founded in the sense of Taylor [16]. Finally, the initial ite...

Recall that for a triangulated category T , a Bousfield localization is an exact functor L : T → T which is coaugmented (there is a natural transformation Id → L; sometimes L is referred to as a pointed endofunctor) and idempotent (there is a natural isomorphism Lη = ηL : L → LL). The kernel ker(L) is the collection of objects X such that LX = 0. If T is closed under coproducts, it’s a localizi...

We prove an analog of the Künneth formula for groups minimal non-degenerate extensions (Lan et al. in Commun Math Phys 351:709–739, 2017) symmetric fusion categories. describe detail structure group a pointed super-Tannakian category. This description resembles that third cohomology finite abelian group. explicitly compute this several concrete examples.

In this paper, we study the relationship between two main categories of S-acts for a monoid S with zero from viewpoint existence projective covers. particular, prove that condition all acts have cover holds in category if and only it pointed acts. Furthermore, connected are cyclic they satisfy ascending chain on subacts.

Schanuel has pointed out that there are mathematically interesting categories whose relationship to the ring of integers is analogous to the relationship between the category of finite sets and the semi-ring of non-negative integers. Such categories are inherently geometrical or topological, in that the mapping to the ring of integers is a variant of Euler characteristic. In these notes, I sket...

Dermatoglyphic studies Carried out in Schizophrenia have been evaluated and critically examined. Methodological errors existing in the previous studies have been pointed out and some guidelines for methodological refinements suggested and a dermatoglyphic corsensus index for diagnosis has been evolved. The heterogeneous nature of schizophrenia, being a group of syndromes, has been unanimously a...

Working in an arbitrary pointed proper model category, we define what it means for a cofibration to have an obstruction theory. We describe the cofibrations that have an obstruction theory with respect to all fibrations. Up to weak equivalence, retract, and cobase change, they are the cofibrations with weakly contractible target. Equivalently, they are the retracts of principal cofibrations. Wi...