scholarly journals From enhanced coinduction towards enhanced induction

2022 ◽  
Vol 6 (POPL) ◽  
pp. 1-29
Author(s):  
Davide Sangiorgi
Keyword(s):  
Closure Properties ◽  
Proof Techniques ◽  
Inductive Relation ◽  
Class Of Functions

There exist a rich and well-developed theory of enhancements of the coinduction proof method, widely used on behavioural relations such as bisimilarity. We study how to develop an analogous theory for inductive behaviour relations, i.e., relations defined from inductive observables. Similarly to the coinductive setting, our theory makes use of (semi)-progressions of the form R->F(R), where R is a relation on processes and F is a function on relations, meaning that there is an appropriate match on the transitions that the processes in R can perform in which the process derivatives are in F(R). For a given preorder, an enhancement corresponds to a sound function, i.e., one for which R->F(R) implies that R is contained in the preorder; and similarly for equivalences. We introduce weights on the observables of an inductive relation, and a weight-preserving condition on functions that guarantees soundness. We show that the class of functions contains non-trivial functions and enjoys closure properties with respect to desirable function constructors, so to be able to derive sophisticated sound functions (and hence sophisticated proof techniques) from simpler ones. We consider both strong semantics (in which all actions are treated equally) and weak semantics (in which one abstracts from internal transitions). We test our enhancements on a few non-trivial examples.

scholarly journals Hayman Admissible Functions in Several Variables

10.37236/1132 ◽  
2006 ◽  
Vol 13 (1) ◽  
Author(s):  
Bernhard Gittenberger ◽  
Johannes Mandlburger
Keyword(s):  
Asymptotic Expansion ◽  
Closure Properties ◽  
Several Variables ◽  
Class Of Functions ◽  
Admissible Functions

An alternative generalisation of Hayman's concept of admissible functions to functions in several variables is developed and a multivariate asymptotic expansion for the coefficients is proved. In contrast to existing generalisations of Hayman admissibility, most of the closure properties which are satisfied by Hayman's admissible functions can be shown to hold for this class of functions as well.

scholarly journals Certain Properties of a Class of Functions Defined by Means of a Generalized Differential Operator

Mathematics ◽  
2022 ◽  
Vol 10 (2) ◽  
pp. 174
Author(s):  
Matthew Olanrewaju Oluwayemi ◽  
Kaliappan Vijaya ◽  
Adriana Cătaş
Keyword(s):  
Differential Operator ◽  
Analytic Functions ◽  
Closure Properties ◽  
Integral Means ◽  
Radius Of Starlikeness ◽  
Generalized Differential ◽  
The Relationship ◽  
Class Of Functions

In this article, we construct a new subclass of analytic functions involving a generalized differential operator and investigate certain properties including the radius of starlikeness, closure properties and integral means result for the class of analytic functions with negative coefficients. Further, the relationship between the results and some known results in literature are also established.

scholarly journals On a New Class ofp-Valent Meromorphic Functions Defined in Conic Domains

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Mohammed Ali Alamri ◽  
Maslina Darus
Keyword(s):  
Hypergeometric Function ◽  
Meromorphic Functions ◽  
Starlike Functions ◽  
Closure Properties ◽  
New Class ◽  
Conic Domain ◽  
Class Of Functions

We define a new class of multivalent meromorphic functions using the generalised hypergeometric function. We derived this class related to conic domain. It is also shown that this new class of functions, under certain conditions, becomes a class of starlike functions. Some results on inclusion and closure properties are also derived.

On the bisimulation proof method

1998 ◽  
Vol 8 (5) ◽  
pp. 447-479 ◽  
Author(s):  
DAVIDE SANGIORGI
Keyword(s):  
Unique Solution ◽  
Simple Form ◽  
Simple Condition ◽  
Process Algebras ◽  
Closure Properties ◽  
Popular Method ◽  
Solution Of Equations ◽  
Proof Techniques ◽  
Π Calculus

The most popular method for establishing bisimilarities among processes is to exhibit bisimulation relations. By definition, [Rscr ] is a bisimulation relation if [Rscr ] progresses to [Rscr ] itself, i.e., pairs of processes in [Rscr ] can match each other's actions and their derivatives are again in [Rscr ].We study generalisations of the method aimed at reducing the size of the relations to be exhibited and hence relieving the proof work needed to establish bisimilarity results. We allow a relation [Rscr ] to progress to a different relation [Fscr ] ([Rscr ]), where [Fscr ] is a function on relations. Functions that can be safely used in this way (i.e., such that if [Rscr ] progresses to [Fscr ] ([Rscr ]), then [Rscr ] only includes pairs of bisimilar processes) are sound. We give a simple condition that ensures soundness. We show that the class of sound functions contains non-trivial functions and we study the closure properties of the class with respect to various important function constructors, like composition, union and iteration. These properties allow us to construct sophisticated sound functions – and hence sophisticated proof techniques for bisimilarity – from simpler ones.The usefulness of our proof techniques is supported by various non-trivial examples drawn from the process algebras CCS and π-calculus. They include the proof of the unique solution of equations and the proof of a few properties of the replication operator. Among these, there is a novel result that justifies the adoption of a simple form of prefix-guarded replication as the only form of replication in the π-calculus.

CLASS OF BOOLEAN FUNCTIONS CONSTRUCTED USING SIGNIFICANT BITS OF LINEAR RECURRENCES OVER THE RING ℤ2n

2019 ◽  
Vol 6 (2) ◽  
pp. 90-94
Author(s):  
Hernandez Piloto Daniel Humberto
Keyword(s):  
Linear Function ◽  
Boolean Functions ◽  
Hamming Distance ◽  
Linear Recurrences ◽  
Maximum Period ◽  
Non Linear ◽  
The Given ◽  
Class Of Functions

In this work a class of functions is studied, which are built with the help of significant bits sequences on the ring ℤ2n. This class is built with use of a function ψ: ℤ2n → ℤ2. In public literature there are works in which ψ is a linear function. Here we will use a non-linear ψ function for this set. It is known that the period of a polynomial F in the ring ℤ2n is equal to T(mod 2)2α, where α∈ , n01- . The polynomials for which it is true that T(F) = T(F mod 2), in other words α = 0, are called marked polynomials. For our class we are going to use a polynomial with a maximum period as the characteristic polyomial. In the present work we show the bounds of the given class: non-linearity, the weight of the functions, the Hamming distance between functions. The Hamming distance between these functions and functions of other known classes is also given.

Some new results on the subexponential class

1989 ◽  
Vol 26 (4) ◽  
pp. 892-897 ◽  
Author(s):  
Emily S. Murphree
Keyword(s):  
Distribution Function ◽  
Sufficient Conditions ◽  
Necessary Condition ◽  
Subexponential Class ◽  
Class Of Functions

A distribution function F on (0,∞) belongs to the subexponential class if the ratio of 1 – F(2)(x) to 1 – F(x) converges to 2 as x →∞. A necessary condition for membership in is used to prove that a certain class of functions previously thought to be contained in has members outside of . Sufficient conditions on the tail of F are found which ensure F belongs to ; these conditions generalize previously published conditions.

scholarly journals On the Boundary Dieudonné–Pick Lemma

Mathematics ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1108
Author(s):  
Olga Kudryavtseva ◽  
Aleksei Solodov
Keyword(s):  
Fixed Point ◽  
Interior Point ◽  
Sharp Estimate ◽  
General Boundary ◽  
Extremal Functions ◽  
Angular Derivative ◽  
Additional Information ◽  
Carathéodory Theorem ◽  
Class Of Functions ◽  
Boundary Fixed Point

The class of holomorphic self-maps of a disk with a boundary fixed point is studied. For this class of functions, the famous Julia–Carathéodory theorem gives a sharp estimate of the angular derivative at the boundary fixed point in terms of the image of the interior point. In the case when additional information about the value of the derivative at the interior point is known, a sharp estimate of the angular derivative at the boundary fixed point is obtained. As a consequence, the sharpness of the boundary Dieudonné–Pick lemma is established and the class of the extremal functions is identified. An unimprovable strengthening of the Osserman general boundary lemma is also obtained.

Coefficient inequalities related with typically real functions

2020 ◽  
Vol 70 (4) ◽  
pp. 829-838
Author(s):  
Saqib Hussain ◽  
Shahid Khan ◽  
Khalida Inayat Noor ◽  
Mohsan Raza
Keyword(s):  
Unit Disk ◽  
Real Functions ◽  
Coefficient Inequalities ◽  
Typically Real ◽  
Class Of Functions ◽  
Typically Real Functions

AbstractIn this paper, we are mainly interested to study the generalization of typically real functions in the unit disk. We study some coefficient inequalities concerning this class of functions. In particular, we find the Zalcman conjecture for generalized typically real functions.

scholarly journals Norm inequalities involving a special class of functions for sector matrices

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Davood Afraz ◽  
Rahmatollah Lashkaripour ◽  
Mojtaba Bakherad
Keyword(s):  
Special Class ◽  
Norm Inequalities ◽  
Class Of Functions

Multiple Regularity and Binary ETOL-Systems1

1981 ◽  
Vol 4 (1) ◽  
pp. 19-34
Author(s):  
Ryszard Danecki
Keyword(s):  
Equivalence Problem ◽  
Tree Automata ◽  
Closure Properties ◽  
Multiple Tree

Closure properties of binary ETOL-languages are investigated by means of multiple tree automata. Decidability of the equivalence problem of deterministic binary ETOL-systems is proved.

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