A5072655052- semigroups and automata theory
- Advanced Algebra and Logic
- History and Theory of Mathematics
- Fuzzy and Soft Set Theory
- Geometric and Algebraic Topology
- Computability, Logic, AI Algorithms
- Planetary Science and Exploration
- Rings, Modules, and Algebras
- Natural Language Processing Techniques
- Astro and Planetary Science
- Advanced Topology and Set Theory
- Algorithms and Data Compression
- Mathematical Dynamics and Fractals
- Space Science and Extraterrestrial Life
- Mathematics and Applications
- DNA and Biological Computing
- Rough Sets and Fuzzy Logic
- Advanced Combinatorial Mathematics
- Advanced Graph Theory Research
- Methane Hydrates and Related Phenomena
- Artificial Intelligence in Games
- Coding theory and cryptography
- Physics and Engineering Research Articles
- Functional Equations Stability Results
- Advanced Differential Equations and Dynamical Systems
University of Toronto
2023-2024
University of Edinburgh
2020-2024
University of Essex
2012-2023
Royal Observatory
2021-2023
UK Astronomy Technology Centre
2021
Colchester Institute
2002
Universidade do Porto
1997
The Royal Melbourne Hospital
1988-1990
RMIT Europe
1990
Deakin University
1985-1988
Titan has an organic-rich atmosphere and surface with a subsurface liquid water ocean that may represent habitable environment. In this work, we determined the amount of organic material can be delivered from Titan's to its through impact cratering. We assumed craters produce melt deposits composed founder in lower-density ice crust estimated molecules could incorporated into these lenses. used known yields for HCN haze hydrolysis determine glycine produced lenses found range possible flux...
Understanding the energy requirements for cell synthesis accurately and comprehensively has been a longstanding challenge. We introduce computational model that estimates minimum necessary to build any from its constituent parts. This method combines omics internal compositions various sources calculate Gibbs Free Energy of biosynthesis independently specific metabolic pathways. Our public tool, Synercell, can be used with other models minumum species-specific estimations in well-sequenced...
The canonical water cycle assumes that all entering the subsurface to form groundwater eventually reenters surface by discharge lakes, streams, and oceans. Recent discoveries in dating have challenged understanding. Here we introduce a new conceptual framework includes large volume of is estimated account for 30–46% planet's but not yet incorporated traditional cycle. This immense hidden hydrogeosphere has been overlooked date largely because it stored deeper crust, on long timescales...
For a semigroup S and set the relative rank of modulo A is minimal cardinality setB such that generates S. We show an infinite full transformation symmetric group, also all idempotent mappings, equal to 2. characterise pairs mappings which, together with group or idempotents, generate semigroup.
Consider the finite set X n = {1,2, …, } ordered in standard way. Let T denote full transformation semigroup on , that is, of all mappings α: → under composition. We shall call α order-preserving if i ≤ j implies for ∈ and is decreasing . This paper investigates combinatorial properties O its subsemigroup C which consists mappings.
Abstract The relative rank $\rank(S:A)$ of a subset $A$ semigroup $S$ is the minimum cardinality set $B$ such that $\langle A\cup B\rangle=S$. It follows from result Sierpiński that, if $X$ infinite, full transformation $\mathcal{T}_{X}$ either uncountable or at most $2$. A similar holds for $\mathcal{B}_{X}$ binary relations on $X$. $\mathcal{T}_{\mathbb{N}}$ dominated (by $U$) there exists countable $U$ with property each $\sigma$ in $\mu$ $i\sigma\le i\mu$ all $i$ $\mathbb{N}$. shown...
If E is the set of idempotents and G group units within a full transformation semigroup ℐ x , then EG = GE if X finite. The question identifying subsemigroup 〈G∪E〉 in case where infinite leads to an investigation interrelations among various naturally occurring subsemigroups . In final section it shown that precisely two additional elements µ, v are needed order G∪E∪{µ, v} should generate
The cloud layer has been hypothesized to be the most habitable region of Venus. In lower clouds, both temperature and pressure fall within bounds that support reproduction microbial life on Earth, although water activity sulfuric acid droplets makes clouds uninhabitable known life. this study, we carried out an analysis CHNOPS (carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur) elements potential redox couples in layer, used a energetic growth model investigate quantitatively chemical...
Abstract In recent years, Enceladus' subsurface ocean has become a tantalizing case study for potentially habitable conditions in an extraterrestrial world. However, we still know very little about its conditions. Its oceanic composition is difficult to characterize with current data and estimates are highly dependent on model‐based interpretations which also not yet tightly constrained. light of these uncertainties, consider wide selection the inferred parameter spaces quantify energy...
An enduring question in astrobiology is how we assess extraterrestrial environments as being suitable for life. We suggest that the most reliable assessments of habitability are made with respect to empirically determined limits known discuss qualitatively distinct categories habitability:
Core share and HTML view are not possible as this article does have html content. However, you access to content, a full PDF is available via the ‘Save PDF’ action button. For linearly ordered set $X$ we consider relative rank of semigroup all order preserving mappings $\mathcal{O}_{X}$ on modulo transformation $\mathcal{T}_{X}$. In other words, ask what smallest cardinality $A$ such that $\genset{\mathcal{O}_{X}\cup A}=\mathcal{T}_{X}$. When countably infinite or well-ordered (of arbitrary...
Abstract We establish a necessary condition ( E ) for semigroup variety to be closed under the taking of epimorphisms and S consist entirely saturated semigroups. Condition is shown sufficient heterotypical varieties stronger ′) homotypical varieties.
The relative rank (S : U) of a subsemigroup U semigroup S is the minimum size set V ⊆ such that together with generates whole S. As consequence result Sierpiński, it follows for ⩽ TX, monoid all self-maps an infinite X, rank(TX either 0, 1 or 2, uncountable. In this paper, ranks OX) are considered, where X countably partially ordered and OX endomorphism X. We show 2 if only either: there exists at least one element in which greater than, less number elements X; has |X| connected components....
In order to grow, reproduce and evolve life requires a supply of energy nutrients. Astrobiology has the challenge studying on Earth in environments which are poorly characterized or extreme, usually both, predicting habitability extraterrestrial environments. We have developed general astrobiological model for assessing energetic nutrient availability predict their potential biological productivity. NutMEG (nutrients, maintenance, growth) can be used estimate how much biomass an environment...
Although the search for habitability is a much-vaunted objective in study of planetary environments, material requirements an environment to be habitable can met with relatively few ingredients. In this hypothesis paper, minimum are first re-evaluated, necessarily based on life "as we know it." From vantage point, explore examples number conditions arise environment, which illustrate "minimum diagrams." These raise that may common throughout universe. If was accepted, then discovery would...
Abstract We characterise the respective semigroups of mappings that preserve, or preserve reverse orientation a finite cycle, in terms their actions on oriented triples and quadruples. This leads to proof latter semigroup coincides with all intersections chords corresponding circle.