The standard semantics for the modal fragment of natural languages can only be correct if there is more than one possible world. The nature and existence of possible worlds is thus of fundamental importance for such a semantics. The paper develops an account of possible worlds in the spirit of the pleonastic account of abstract entities in general, due to Stephen Schiffer (2003: ch. 2). The mai...

We solve the problem of computing the residual reliability (the RES problem) for all classes of P-threshold graphs for which efficient structural characterizations based on decomposition to indecomposable components have been established. In particular, we give a constructive proof of existence of linear algorithms for computing residual reliability of pseudodomishold, domishold, matrogenic and...

Using language of dg PROPs we give a new short proof of existence of star products on (formal) germs of Poisson manifolds.

Using language of dg PROPs we give a new proof of existence of star products on (formal) germs of Poisson manifolds.

We provide cubature formulas for the calculation of derivatives of expected values in the spririt of Terry Lyons and Nicolas Victoir. In financial mathematics derivatives of option prices with respect to initial values, so called Greeks, are of particular importance as hedging parameters. The proof of existence of Cubature formulas for Greeks is based on an argument, which leads to the calculat...

In an earlier paper we supplied indirect proof of the existence universal possible worlds that have topological property being hypercyclic, which means they can access every world in sequences approach arbitrarily closely to world. That states there are but it does not exhibit such a explicitly. We now explicitly construct two worlds. A continuous constructs with transreal co-ordinates directly...

In 1984, Raoult proposed a formalization of graph rewritings using pushouts in the category of graphs and partial functions. This note generalizes his method and formulates algebraic graph structure to introduce a more general framework for graph rewritings and to give a simple proof of existence theorem of pushouts using relational calculus.

We present a computer assisted proof of existence of a family of Lyapunov orbits which stretches from L2 (the collinear libration point between the primaries) up to half the distance to the smaller primary in the Jupiter-Sun planar circular restricted three body problem. We then focus on a small family of Lyapunov orbits with energies close to comet Oterma and show that their associated invaria...

We describe a set of algorithms (and corresponding codes) that serve as a basis for an automated proof of existence of a certain dynamical behaviour in a given dynamical system. In particular it is in principle possible to automatically verify the presence of complicated dynamics using these tools. The Hénon map is used to illustrate these techniques.

In 1970, E. M. Andreev published a classification of all three dimensional compact hyperbolic polyhedra having non-obtuse dihedral angles [3]. Given a combinatorial description of a polyhedron, C, Andreev’s Theorem provides five classes of linear inequalities, depending on C, for the dihedral angles, which are necessary and sufficient conditions for the existence of a hyperbolic polyhedron real...