In his famous book “Combinatory Analysis” MacMahon introduced Partition Analysis (“Omega Calculus”) as a computational method for solving problems in connection with linear homogeneous diophantine inequalities and equations. The object of this paper is to show that partition analysis is ideally suited for being implemented in computer algebra. To this end we have developed the computer algebra ...

Weak omega algebra and demonic refinement algebra are two ways of describing systems with finite and infinite iteration. We show that these independently introduced kinds of algebras can actually be defined in terms of each other. By defining modal operators on the underlying weak semiring, that result directly gives a demonic refinement algebra of commands. This yields models in which extensio...

We propose a relaxation of Kleene algebra by giving up strictness and right-distributivity of composition. This allows the subsumption of Dijkstra’s computation calculus, Cohen’s omega algebra and von Wright’s demonic refinement algebra. Moreover, by adding domain and codomain operators we can also incorporate modal operators. Finally, it is shown that the predicate transformers form lazy Kleen...

Abstract In this paper, we show that Leavitt path algebras of weighted graphs and separated are intimately related. We prove any algebra $L(E,\omega )$ a row-finite vertex graph $(E,\omega is $*$ -isomorphic to the lower certain bipartite $(E(\omega ),C(\omega ))$ . For general locally finite $(E, \omega , quotient $L_1(E,\omega an upper another $(E(w)_1,C(w)^1)$ furthermore introduce ${L^{\mat...

We propose a relaxation of Kleene algebra by giving up strictness and right-distributivity of composition. This allows the subsumption of Dijkstra’s computation calculus, Cohen’s omega algebra and von Wright’s demonic refinement algebra. Moreover, by adding domain and codomain operators we can also incorporate modal operators. We show that predicate transformers form lazy Kleene algebras, the d...

Omega-regular algebras axiomatise the equational theory of omega-regular expressions as induced by omega-regular language identity. Wagner presented an omega-regular algebra which requires recursively defined side conditions in some of its axioms. We introduce a first-order Horn axiomatisation for which such conditions can be avoided because additive and multiplicative units are absent. We prov...

Typed omega algebras extend Kozen’s typed Kleene algebras by an operation for infinite iteration in a similar way as Cohen’s omega algebras extend Kleene algebras in the untyped case. Typing these algebras is motivated by non-square matrices in automata constructions and applications in program semantics. For several reasons – the theory of untyped (Kleene or omega) algebras is well developed, ...

We generalise the designs of the Unifying Theories of Programming (UTP) by defining them as matrices over semirings with ideals. This clarifies the algebraic structure of designs and considerably simplifies reasoning about them, for example, since they form a Kleene and omega algebra and a test semiring. We apply our framework to investigate symmetric linear recursion and its relation to tail-r...

Utilizing the linking algebra of a Hilbert $C^*$-module $\big(\mathscr{V}, {\|\!\cdot\!\|}_{_{\mathscr{V}}}\big)$, we introduce $\Omega(x)$ as definition numerical radius for an element $x\in\mathscr{V}$ and then show that $\Omega(\cdot)$ is norm on $\mathscr{V}$ such $\frac{1}{2}{\|x\|}_{_{\mathscr{V}}} \leq \Omega(x) {\|x\|}_{_{\mathscr{V}}}$. In addition, obtain equivalent condition $\Omega(...