126 research outputs found
The Tree Width of Separation Logic with Recursive Definitions
Separation Logic is a widely used formalism for describing dynamically
allocated linked data structures, such as lists, trees, etc. The decidability
status of various fragments of the logic constitutes a long standing open
problem. Current results report on techniques to decide satisfiability and
validity of entailments for Separation Logic(s) over lists (possibly with
data). In this paper we establish a more general decidability result. We prove
that any Separation Logic formula using rather general recursively defined
predicates is decidable for satisfiability, and moreover, entailments between
such formulae are decidable for validity. These predicates are general enough
to define (doubly-) linked lists, trees, and structures more general than
trees, such as trees whose leaves are chained in a list. The decidability
proofs are by reduction to decidability of Monadic Second Order Logic on graphs
with bounded tree width.Comment: 30 pages, 2 figure
The Complexity of Repairing, Adjusting, and Aggregating of Extensions in Abstract Argumentation
We study the computational complexity of problems that arise in abstract
argumentation in the context of dynamic argumentation, minimal change, and
aggregation. In particular, we consider the following problems where always an
argumentation framework F and a small positive integer k are given.
- The Repair problem asks whether a given set of arguments can be modified
into an extension by at most k elementary changes (i.e., the extension is of
distance k from the given set).
- The Adjust problem asks whether a given extension can be modified by at
most k elementary changes into an extension that contains a specified argument.
- The Center problem asks whether, given two extensions of distance k,
whether there is a "center" extension that is a distance at most (k-1) from
both given extensions.
We study these problems in the framework of parameterized complexity, and
take the distance k as the parameter. Our results covers several different
semantics, including admissible, complete, preferred, semi-stable and stable
semantics
Synaptic abnormalities in the infralimbic cortex of a model of congenital depression
Multiple lines of evidence suggest that disturbances in excitatory transmission contribute to depression. Whether these defects involve the number, size, or composition of glutamatergic contacts is unclear. This study used recently introduced procedures for fluorescence deconvolution tomography in a well-studied rat model of congenital depression to characterize excitatory synapses in layer I of infralimbic cortex, a region involved in mood disorders, and of primary somatosensory cortex. Three groups were studied: (1) rats bred for learned helplessness (cLH); (2) rats resistant to learned helplessness (cNLH); and (3) control Sprague Dawley rats. In fields within infralimbic cortex, cLH rats had the same numerical density of synapses, immunolabeled for either the postsynaptic density (PSD) marker PSD95 or the presynaptic protein synaptophysin, as controls. However, PSD95 immunolabeling intensities were substantially lower in cLH rats, as were numerical densities of synapse-sized clusters of the AMPA receptor subunit GluA1. Similar but less pronounced differences (comparable numerical densities but reduced immunolabeling intensity for PSD95) were found in the somatosensory cortex. In contrast, non-helpless rats had 25% more PSDs than either cLH or control rats without any increase in synaptophysin-labeled terminal frequency. Compared with controls, both cLH and cNLH rats had fewer GABAergic contacts. These results indicate that congenital tendencies that increase or decrease depression-like behavior differentially affect excitatory synapses
On the Monadic Second-Order Transduction Hierarchy
We compare classes of finite relational structures via monadic second-order
transductions. More precisely, we study the preorder where we set C \subseteq K
if, and only if, there exists a transduction {\tau} such that
C\subseteq{\tau}(K). If we only consider classes of incidence structures we can
completely describe the resulting hierarchy. It is linear of order type
{\omega}+3. Each level can be characterised in terms of a suitable variant of
tree-width. Canonical representatives of the various levels are: the class of
all trees of height n, for each n \in N, of all paths, of all trees, and of all
grids
Compact Labelings For Efficient First-Order Model-Checking
We consider graph properties that can be checked from labels, i.e., bit
sequences, of logarithmic length attached to vertices. We prove that there
exists such a labeling for checking a first-order formula with free set
variables in the graphs of every class that is \emph{nicely locally
cwd-decomposable}. This notion generalizes that of a \emph{nicely locally
tree-decomposable} class. The graphs of such classes can be covered by graphs
of bounded \emph{clique-width} with limited overlaps. We also consider such
labelings for \emph{bounded} first-order formulas on graph classes of
\emph{bounded expansion}. Some of these results are extended to counting
queries
The Grizzly, April 15, 1983
Second Attack: Improvements Sought for Security • New Senior Fund • Seminar Planned • The A\u27s Come to Helfferich Hall • Letter to the Editor: Most Abominable Act • Faculty Promotions Approved • President\u27s Corner • Sexual Assault in Quad • Security Tips • Nuclear Freeze Concert • Ursinus Representatives at UN • Ice Cream Night at Bear\u27s Den • Final Exam Schedule • Republicans for Rock! • Escape From Ursinus • Bear Batsmen Drop Slugfest • Men\u27s Track Evens Up • Men\u27s Tennis Nets Two Wins • Girls\u27 Nets Optimistic • Men\u27s Lacrosse Victorioushttps://digitalcommons.ursinus.edu/grizzlynews/1098/thumbnail.jp
Packing and covering immersion models of planar subcubic graphs
A graph is an immersion of a graph if can be obtained by some
sugraph after lifting incident edges. We prove that there is a polynomial
function , such that if is a
connected planar subcubic graph on edges, is a graph, and is a
non-negative integer, then either contains vertex/edge-disjoint
subgraphs, each containing as an immersion, or contains a set of
vertices/edges such that does not contain as an
immersion
The Grizzly, March 25, 1983
New Editors Elected: Romer, Hong, Pasekoff Named • Superstars Tournament Needs Participants • DuPont Gives Third Consecutive Chemistry Grant • The A\u27s Come to UC • Third Annual Special Olympics This Weekend • Summer in Japan • Folk Singers at Bomberger • Letters to the Editor: An Epilogue to Zeta Chi • USGA Holds Election • USGA Notes • Voight at Bat • 13 Spend Break in Quebec • To Hell With the USFL • College Bowl Goes to Maryland • 1983 Room Selection Procedure • Bear\u27s Den Replaces Cafe International • Cycling Marathon: Ride for Your Life • Men\u27s Lacrosse Slow Getting Started • Men\u27s and Women\u27s Track Win Openershttps://digitalcommons.ursinus.edu/grizzlynews/1097/thumbnail.jp
The Grizzly, March 23, 1984
Assault Attempt on Ursinus Female • Speaker Gives Business Pointers • Forced Bussing in Wismer • New Course for Comm Arts Minor • Letters to the Editor • 1984 Fraternity Pledging Ends • New Fine Arts Course Planned for Fall • In my Opinion: Pledging Should be Banned • Meistersingers Give Return Performance • UC Sponsors Science Competition • Dr. Clouser Delivers Goethe Lecture • Lift-A-Thon Raises Funds for New Equipment • Bear Blades Remain Undefeated • Housing Changes Imminent • Orchestra Presents Bach Festival • Aquabears Conclude Best Season Ever • Batsmen Victorious in Opener • Men\u27s Lacrosse Optimistic • Track Team Looking Solidhttps://digitalcommons.ursinus.edu/grizzlynews/1115/thumbnail.jp
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