Tree-compositions and orientations

Tree-compositions and orientations

A tree-composition is a tree-like family that serves to describe the obstacles to k-edge-connected orientability of mixed graphs. Here we derive a structural result on tree-compositions that gives rise to a simple algorithm for computing an obstacle when the orientation does not exist. As another application, we show a min–max theorem on the minimal in-degree of a given node set in a k-edge-con...

Compositions of tree series transformations

Tree series transformations computed by bottom-up and top-down tree series transducers are called bottomup and top-down tree series transformations, respectively. (Functional) compositions of such transformations are investigated. It turns out that the class of bottom-up tree series transformations over a commutative and complete semiring is closed under left-composition with linear bottom-up t...

On optimal orientations of tree vertex-multiplications

Compositions of Tree-to-Tree Statistical Machine Translation Models

Compositions of well-known tree-to-tree translation models used in statistical machine translation are investigated. Synchronous context-free grammars are closed under composition in both the unweighted as well as the weighted case. In addition, it is demonstrated that there is a close connection between compositions of synchronous tree-substitution grammars and compositions of certain tree tra...

Compositions of Bottom-Up Tree Series Transformations

Tree series transformations computed by bottom-up tree series transducers are called bottom-up tree series transformations. (Functional) compositions of such transformations are investigated. It turns out that bottom-up tree series transformations over commutative and א0-complete semirings are closed under left-composition with linear bottom-up tree series transformations and right-composition ...