Many-one degrees associated with problems of tag

1973 ◽  
Vol 38 (1) ◽  
pp. 1-17 ◽  
Author(s):  
C. E. Hughes
Keyword(s):  
Formal Proof ◽  
Extensive Study ◽  
Decision Problems ◽  
Turing Machines ◽  
Natural Numbers ◽  
Halting Problem ◽  
The Family ◽  
Form Part ◽  
The Many ◽  
Degrees Of Unsolvability

Tag systems were defined by Post [9], [10] and have been studied by a number of researchers including Minsky [7], Maslov [6] and Aanderaa and Belsnes [1]. In their recent paper Aanderaa and Belsnes demonstrated that every r.e. many-one degree (exclusive of the degree of the empty set) is represented by the general halting problem for tag systems, that is, by the family of halting problems ranging over all tag systems. Their result depends upon an informal proof of this property for Turing machines but may be seen to be correct in light of a formal proof due to Overbeek [8]. Our aim is to extend their results to the general word problem for these systems. Specifically, we shall present an effective method which, when applied to an arbitrary r.e. set S, where S is neither empty nor the set of all natural numbers, produces a tag system R′ whose word and halting problems are both of the same many-one degree as the decision problem for S. The proof is realized by first constructing, from the description of an arbitrary Turing machine M, which machine has at least one mortal and one immortal configuration, a 5-register machine R, whose word and halting problems are both of the same many-one degree as the halting problem for M. From R we then construct the desired tag system R′. This construction combined with Overbeek's [8] shows that every r.e. many-one degree (exclusive of the degrees of the empty set and the set of all natural numbers) is represented by the general word and halting problems for tag systems. Moreover our results are seen to be best possible with regard to degrees of unsolvability in that it is not the case that every nonrecursive r.e. one-one degree is represented by either of the general decision problems for tag systems which are considered here. These results were first shown in the author's thesis [3] and were announced in [4], They form part of an extensive study into the many-one equivalence of general decision problems. An overview of the initial findings of this research project may be found in [5].

Two variable implicational calculi of prescribed many-one degrees of unsolvability

1976 ◽  
Vol 41 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Charles E. Hughes
Keyword(s):  
Decision Problems ◽  
Constructive Proof ◽  
Distinct Variable ◽  
The Family ◽  
Propositional Calculi ◽  
Degrees Of Unsolvability

AbstractA constructive proof is given which shows that every nonrecursive r.e. many-one degree is represented by the family of decision problems for partial implicational propositional calculi whose well-formed formulas contain at most two distinct variable symbols.

Research into psychosocial issues

2021 ◽  
pp. 1295-1311
Author(s):  
David W. Kissane ◽  
Christopher H. Grossman ◽  
Clare O’Callaghan
Keyword(s):  
Quality Of Life ◽  
Family Caregiving ◽  
Social Issues ◽  
Death And Dying ◽  
Extensive Study ◽  
Research Outcomes ◽  
The Family ◽  
The Many ◽  
Study Designs

Psychological, existential, spiritual, and social issues cause much suffering and deserve extensive study to understand these concerns more fully and to intervene more effectively. Themes that abound include communication, coping, ethics, the family, caregiving, quality of life, death and dying, psychiatric disorders, suffering, and the many expressions of distress. Many study designs are possible to explore these themes, often with complementary quantitative and qualitative components. This chapter summarizes the psychometric properties of many of the instruments that are commonly employed in such studies, and describes quantitative, qualitative, and mixed methods designs used. The goal is to strengthen research design and optimize research outcomes to benefit the discipline.

Research into psychosocial issues

2015 ◽  
Author(s):  
David W. Kissane ◽  
Annette F. Street ◽  
Erin E. Schweers ◽  
Thomas M. Atkinson
Keyword(s):  
Family Caregiving ◽  
Social Issues ◽  
Death And Dying ◽  
Extensive Study ◽  
Computer Assisted ◽  
Software Packages ◽  
The Family ◽  
The Many ◽  
Study Designs

Psychological, existential, spiritual, and social issues cause much suffering and deserve extensive study to understand these concerns more fully and to intervene more effectively. Themes that abound include communication, coping, ethics, the family, caregiving, quality of life, death and dying, psychiatric disorders, suffering, and the many expressions of distress. Many study designs are possible to explore these themes, often with complementary quantitative and qualitative components. This chapter summarizes the psychometric properties of many of the instruments that are commonly employed in such studies and the computer-assisted software packages that assist qualitative analyses. The goal is to strengthen research design and optimize research outcomes to benefit the discipline.

A General Framework for Priority Arguments

1995 ◽  
Vol 1 (2) ◽  
pp. 189-201 ◽  
Author(s):  
Steffen Lempp ◽  
Manuel Lerman
Keyword(s):  
Information Content ◽  
Equivalence Relation ◽  
Decision Problem ◽  
General Framework ◽  
Equivalence Classes ◽  
Partial Ordering ◽  
Decision Problems ◽  
Natural Numbers ◽  
Relative Complexity ◽  
Degrees Of Unsolvability

The degrees of unsolvability were introduced in the ground-breaking papers of Post [20] and Kleene and Post [7] as an attempt to measure theinformation contentof sets of natural numbers. Kleene and Post were interested in the relative complexity of decision problems arising naturally in mathematics; in particular, they wished to know when a solution to one decision problem contained the information necessary to solve a second decision problem. As decision problems can be coded by sets of natural numbers, this question is equivalent to: Given a computer with access to an oracle which will answer membership questions about a setA, can a program (allowing questions to the oracle) be written which will correctly compute the answers to all membership questions about a setB? If the answer is yes, then we say thatBisTuring reducibletoAand writeB≤TA. We say thatB≡TAifB≤TAandA≤TB. ≡Tis an equivalence relation, and ≤Tinduces a partial ordering on the corresponding equivalence classes; the poset obtained in this way is called thedegrees of unsolvability, and elements of this poset are calleddegrees.Post was particularly interested in computability from sets which are partially generated by a computer, namely, those for which the elements of the set can be enumerated by a computer.

Some undecidability results in strong algebraic languages

1984 ◽  
Vol 49 (3) ◽  
pp. 951-954
Author(s):  
Cornelia Kalfa
Keyword(s):  
Decision Problem ◽  
Decision Problems ◽  
Turing Machines ◽  
Constant Symbol ◽  
Finite Sets ◽  
Operation Symbol ◽  
Halting Problem ◽  
First Order ◽  
Order Language ◽  
Image Position

The recursively unsolvable halting problem for Turing machines is reduced to the problem of the existence or not of an algorithm for deciding whether a field is finite. The latter problem is further reduced to the decision problem of each of propertiesfor recursive sets Σ of equations of strong algebraic languages with infinitely many operation symbols.Decision problems concerning properties of sets of equations were first raised by Tarski [9] and subsequently examined by Perkins [6], McKenzie [4], McNulty [5] and Pigozzi [7]. Perkins is the only one who studied recursive sets; the others investigated finite sets. Since the undecidability of properties Pi for recursive sets of equations does not imply any answer to the corresponding decision problems for finite sets, the latter problems remain open.The work presented here is part of my Ph.D. thesis [2]. I thank Wilfrid Hodges, who supervised it.An algebraic language is a first-order language with equality but without relation symbols. It is here denoted by , where Qi is an operation symbol and cj, is a constant symbol.

scholarly journals Actin-membrane interaction in fibroblasts: what proteins are involved in this association?

1984 ◽  
Vol 99 (1) ◽  
pp. 95s-103s ◽  
Author(s):  
P Mangeat ◽  
K Burridge
Keyword(s):  
Plasma Membrane ◽  
Actin Filaments ◽  
Stress Fiber ◽  
Membrane Interaction ◽  
Microfilament Bundles ◽  
The Family ◽  
Form Part ◽  
Membrane Attachment ◽  
A Chain ◽  
And Function

In this review we discuss some of the proteins for which a role in linking actin to the fibroblast plasma membrane has been suggested. We focus on the family of proteins related to erythrocyte spectrin, proteins that have generally been viewed as having an organization and a function in actin-membrane attachment similar to those of erythrocyte spectrin. Experiments in which we precipitated the nonerythrocyte spectrin within living fibroblasts have led us to question this supposed similarity of organization and function of the nonerythrocyte and erythrocyte spectrins. Intracellular precipitation of fibroblast spectrin does not affect the integrity of the major actin-containing structures, the stress fiber microfilament bundles. Unexpectedly, however, we found that the precipitation of spectrin results in a condensation and altered distribution of the vimentin class of intermediate filaments in most cells examined. Although fibroblast spectrin may have a role in the attachment of some of the cortical, submembranous actin, it is surprising how little the intracellular immunoprecipitation of the spectrin affects the cells. Several proteins have been found concentrated at the ends of stress fibers, where the actin filaments terminate at focal contacts. Two of these proteins, alpha-actinin and fimbrin, have properties that suggest that they are not involved in the attachment of the ends of the bundles to the membrane but are more probably involved in the organization and cross-linking of the filaments within the bundles. On the other hand, vinculin and talin are two proteins that interact with each other and may form part of a chain of attachments between the ends of the microfilament bundles and the focal contact membrane. Their role in this attachment, however, has not been established and further work is needed to examine their interaction with actin and to identify any other components with which they may interact, particularly in the plasma membrane.

Two primitive trematopid amphibians (Temnospondyli, Dissorophoidea) from the Upper Carboniferous of the Czech Republic

2018 ◽  
Vol 109 (1-2) ◽  
pp. 201-223 ◽  
Author(s):  
Andrew R. MILNER
Keyword(s):  
Czech Republic ◽  
The Czech Republic ◽  
Upper Carboniferous ◽  
Incertae Sedis ◽  
Terminal Form ◽  
The Family ◽  
Nasal Region ◽  
The Many

ABSTRACTSpecimens of trematopid amphibians from the Asturian (Upper Carboniferous) of Nýřany, Czech Republic, are redescribed as two taxa, namely Mordex calliprepes Steen and Mattauschia (gen. nov) laticeps Fritsch. Mordex calliprepes is represented by a single post-metamorphic specimen and has the diagnostic trematopid characters of the nasal region. Mattauschia laticeps is represented by one adult partial skull and mandible plus some fragments and two small post-metamorphic specimens including the species name-bearer. It has the trematopid-type modified lacrimal and a large but oval naris and appears to be the most primitive trematopid yet described. The stratigraphically sequential large trematopids Mattauschia, Fedexia, Ecolsonia and Acheloma show progressive acquisition of the derived features that characterise the terminal form Acheloma.Mordex has a combination of primitive and derived characters and its position within the family is less clear. The many ‘branchiosaurs' in the Nýřany assemblage include specimens that could be larvae of both Mordex and Mattauschia but certain attribution is not possible and they are assigned to Olsoniformes incertae sedis. Mordex and Mattauschia appear to be terrestrial exotic elements in the Nýřany tetrapod assemblage, but with possible larvae in the lake assemblage. Representatives of at least four Palaeozoic dissorophoid families were present in late Middle Pennsylvanian/Asturian strata implying diversification of the Dissorophoidea prior to this time.

scholarly journals „Kochany Tadziku…” – listy Teodora i Eleonory Parnickich do rodziny Banasiów (prefaced and edited by Piotr Gorliński-Kucik)

2019 ◽  
Vol 14 (2) ◽  
pp. 189-223
Author(s):  
Piotr Gorliński-Kucik
Keyword(s):  
The Family ◽  
Valuable Element ◽  
The Many

The letters from Teodor Parnicki, first sent during his years as an émigré in Mexico, and then from Poland, are a vocal testimony to the many years of friendship between the said novelist and Tadeusz Banaś and his family. Aside from recollections of Lviv (then Polish Lwów), where the two initiated their relationship while being in-volved in Sygnały magazine during interwar years, another valuable element of the correspondence in question is Parnicki’s translation of Valery Bryusov’s poem Cienie [Shadows], as well as (quoted by Parnicki entirely from his memory) a poem by Tadeusz Hollender Pochwała Parnickiego i filozofii jego (A Praise of Parnicki and His Philosophy). The collection is concluded by two letters written by Eleonora Parnicka, sent to the family Banaś after her husband’s death in 1988.

scholarly journals Flag brands as factor and results of a country identity and image: Polish experiences

2006 ◽  
pp. 141
Author(s):  
Anna Maria Nikodemska-Wolowik
Keyword(s):  
European Union ◽  
Developed Countries ◽  
Brand Identity ◽  
The European Union ◽  
National Brand ◽  
Consumer Ethnocentrism ◽  
Regional Trends ◽  
The Family ◽  
Form Part ◽  
Sobre Todo

This article discusses the issue of creating regional and country brands by enterprises and of establishing a national brand. The three mentioned flag brand categories have been described in detail and the relations between them have been indicated. The article also makes an attempt at analyzing the factors that form part of the brand identity focusing primarily on the consumer product brands. The identity and image concepts are presented also in a broader perspective as certain attributes that characterize the enterprise itself. The presented considerations refer mainly to Polish companies, but some examples of enterprises from highly developed countries, especially from the European Union, have also been added in order to provide this paper with more practical dimensions. Specific brands offered by national enterprises that may be called country and regional brands have been proposed. Some transformations of the market environment which imply branding activities of the companies have been identified, especially the antiglobalist movement which becomes more and more powerful and its activities directed against big concerns and omnipresent mass brands. Moreover, the consumer ethnocentrism and regional trends opposed to the globalization have been emphasized. Also the important rote of family businesses in developing flag brands has been made evident. The family companies may contribute to maintaining and reinforcing the Polish identity.<br /><br />El presente trabajo se ocupa de los aspectos referentes a la creación de marcas regionales y locales así como del establecimiento de una marca nacional. Las tres categorías de marcas de bandera se han caracterizado detalladamente y se indican las relaciones que existen entre ellas. También se intenta analizar los factores que forman parte de la identidad de marca, con especial atención a las marcas de productos de consumo. Se presentan los conceptos de identidad e imagen desde una perspectiva más amplia como atributos que caracterizan a la empresa. Las reflexiones presentadas se refieren, sobre todo, a las empresas polacas, pero también se citan algunos ejemplos de actividades de compañías localizadas en países altamente desarrollados, en concreto en la Unidad Europea, con el fin de otorgar al artículo una dimensión práctica. Se proponen marcas concretas que ofrecen empresas locales y que pueden denominarse como marcas nacionales o regionales. Se indican los cambios en el entorno del mercado que implican actividades de las empresas en el área de branding, y de modo especial se toma en consideración el cada vez más fuerte movimiento antiglobalizante y sus actividades dirigidas contra grandes consorcios y las omnipresentes marcas de masas. Además se pone de relieve el significado de etnocentrismo de tos consumidores y de las tendencias regionalistas opuestas a la globalización. Del mismo modo, se destaca el importante papel de las empresas familiares en el establecimiento de marcas de bandera. Las empresas familiares podrán contribuir a conservar y reforzar la identidad polaca

Sign in / Sign up

Export Citation Format

Share Document