On a Conjecture of Schnoebelen
نویسندگان
چکیده
The notion of sequential and parallel decomposition of a language over a set of languages was introduced by Schnoebelen. A language is decomposable if it belongs to a finite set of languages S such that each member of S admits a sequential and parallel decomposition over S. We disprove a conjecture of Schnoebelen concerning decomposable languages and establish some new properties of these languages.
منابع مشابه
On Functions Weakly Computable by Petri Nets and Vector Addition Systems
We show that any unbounded function weakly computable by a Petri net or a VASS cannot be sublinear. This answers a long-standing folklore conjecture about weakly computing the inverses of some fast-growing functions. The proof relies on a pumping lemma for sets of runs in Petri nets or VASSes.
متن کاملOn some generalisations of Brown's conjecture
Let $P$ be a complex polynomial of the form $P(z)=zdisplaystyleprod_{k=1}^{n-1}(z-z_{k})$,where $|z_k|ge 1,1le kle n-1$ then $ P^prime(z)ne 0$. If $|z|
متن کاملA note on Fouquet-Vanherpe’s question and Fulkerson conjecture
The excessive index of a bridgeless cubic graph $G$ is the least integer $k$, such that $G$ can be covered by $k$ perfect matchings. An equivalent form of Fulkerson conjecture (due to Berge) is that every bridgeless cubic graph has excessive index at most five. Clearly, Petersen graph is a cyclically 4-edge-connected snark with excessive index at least 5, so Fouquet and Vanherpe as...
متن کامل$L^p$-Conjecture on Hypergroups
In this paper, we study $L^p$-conjecture on locally compact hypergroups and by some technical proofs we give some sufficient and necessary conditions for a weighted Lebesgue space $L^p(K,w)$ to be a convolution Banach algebra, where $1<p<infty$, $K$ is a locally compact hypergroup and $w$ is a weight function on $K$. Among the other things, we also show that if $K$ is a locally compact hyper...
متن کاملOn the oriented perfect path double cover conjecture
An oriented perfect path double cover (OPPDC) of a graph $G$ is a collection of directed paths in the symmetric orientation $G_s$ of $G$ such that each arc of $G_s$ lies in exactly one of the paths and each vertex of $G$ appears just once as a beginning and just once as an end of a path. Maxov{'a} and Ne{v{s}}et{v{r}}il (Discrete Math. 276 (2004) 287-294) conjectured that ...
متن کامل