Nonconvergence, Undecidability, and Intractability in Asymptotic Problems

https://deepblue.lib.umich.edu/bitstream/2027.42/154144/1/39015099114582.pd

Logical limit laws for minor-closed classes of graphs

Let $\mathcal G$ be an addable, minor-closed class of graphs. We prove that the zero-one law holds in monadic second-order logic (MSO) for the random graph drawn uniformly at random from all {\em connected} graphs in $\mathcal G$ on $n$ vertices, and the convergence law in MSO holds if we draw uniformly at random from all graphs in $\mathcal G$ on $n$ vertices. We also prove analogues of these results for the class of graphs embeddable on a fixed surface, provided we restrict attention to first order logic (FO). Moreover, the limiting probability that a given FO sentence is satisfied is independent of the surface $S$. We also prove that the closure of the set of limiting probabilities is always the finite union of at least two disjoint intervals, and that it is the same for FO and MSO. For the classes of forests and planar graphs we are able to determine the closure of the set of limiting probabilities precisely. For planar graphs it consists of exactly 108 intervals, each of length $\approx 5\cdot 10^{-6}$. Finally, we analyse examples of non-addable classes where the behaviour is quite different. For instance, the zero-one law does not hold for the random caterpillar on $n$ vertices, even in FO.Comment: minor changes; accepted for publication by JCT

On Zero-One and Convergence Laws for Graphs Embeddable on a Fixed Surface

We show that for no surface except for the plane does monadic second-order logic (MSO) have a zero-one-law - and not even a convergence law - on the class of (connected) graphs embeddable on the surface. In addition we show that every rational in [0,1] is the limiting probability of some MSO formula. This strongly refutes a conjecture by Heinig et al. (2014) who proved a convergence law for planar graphs, and a zero-one law for connected planar graphs, and also identified the so-called gaps of [0,1]: the subintervals that are not limiting probabilities of any MSO formula. The proof relies on a combination of methods from structural graph theory, especially large face-width embeddings of graphs on surfaces, analytic combinatorics, and finite model theory, and several parts of the proof may be of independent interest. In particular, we identify precisely the properties that make the zero-one law work on planar graphs but fail for every other surface

Monadic Conditionality

The problematic vagueness inherent to the study of being requires an approach that transcends the use of a methodology pertaining to solely one research area. In the following pages we will explore the categories of being, their metaphysical meaning and their interrelations, approaching them via heuristic methods that incorporate symbolic mathematical abstraction and music theory analogies. We will propose a monadic system for explicating how the modes of being interact with each other, also exposing a harmonic model of the universe derived from these hypotheses (Chapter I). The nature of consciousness and its properties will be investigated in Chapter II, followed by a research concerning possible internal self-adjustments of total-being-for-itself that might offer insights regarding the temporality and necessity of individual consciousnesses. The aim of this paper is to coalesce the categories of being (in-itself, for-itself, the Others) into a comprehensive system that could account as a unified ontological model compatible with inferences related to phenomenal manifestations