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axiomatic theories of metacategories and supercategories (Axiom)

Introduction

This is a topic on the axioms of categories, metacategories and supercategories that are relevant, respectively, to mathematics and meta-mathematics. Lawvere's elementary theory of abstract categories (ETAC) provides an axiomatic construction of the theory of categories and functors. Intuitively, with this terminology and axioms, a category is meant to be any structure which is a direct interpretation of ETAC. A functor is then understood to be a triple consisting of two such categories and of a rule F (`the functor') which assigns to each arrow or morphism x of the first category, a unique morphism, written as `F(x)' of the second category, in such a way that the usual two conditions on both objects and arrows in the standard functor definition are fulfilled –the functor is well behaved, i.e., it carries object identities to image object identities, and commutative diagrams to image commmutative diagrams of the corresponding image objects and image morphisms. At the next level, one then defines natural transformations or functorial morphisms between functors as meta-level abbreviated formulas and equations pertaining to commutative diagrams of the distinct images of two functors acting on both objects and morphisms. As the name indicates natural transformations are also well–behaved in terms of the ETAC equations that are satisfied by natural transformations.

ETAS and ETAC

Categories were defined in refs. [9,10] as mathematical interpretations of the `elementary theory of abstract categories' (ETAC). One can generalize the theory of categories to higher dimensions– as in higher dimensional algebra (HDA)– by defining multiple composition laws and allowing higher dimensional, functorial morphisms of several variables to be employed in such higher dimensional structures. Thus, one can introduce an elementary theory of supercategories (ETAS;([1,2]) as a natural extension of Lawvere's ETAC theory to higher dimensions ([7]). Then, supercategories can be defined as mathematical interpretations of the ETAS axioms as in ref.[1].
Definition 0.1   A concrete metagraph $\mathcal{M}_G$ consists of objects, $A, B, C,$... and arrows $f, g, h,$... between objects, and two operations as follows:
  • a domain operation, $dom$, which assigns to each arrow $f$ an object $A~ =~dom ~f$
  • a codomain operation, $cod$, which assigns to each arrow $f$ an object $B~ = ~cod ~f,$ represented as $f: A \to B$ or $A \stackrel{f}{\longrightarrow} B$
Remark 0.1   Related concepts to the general notion of a supercategory recalled above can also be rendered graphically on a computer as a multigraph or a hypergraph. More generally, the class of metagraphs can be also defined as a specific class of supercategories. On the other hand, a supercomputer architecture and operating system software are examples of realizations of relatively simple, or lower dimensional supercategories, as explained in further detail in the next subsections.

ETAS Axioms:

  1. (S1). All symbols, formulas and the eight axioms defined in ETAC are, respectively, also ETAS symbols, formulas and axioms; thus, for any letters $x, y, i, u, A, B$, and unary function symbols $\Delta_0$ and $\Delta_1$, and composition laws $\Gamma_i$, the following are defined as formulas: $\Delta_0 (x) = A$, $\Delta_1 (x) = B$, $\Gamma (x,y;u)$, and $x = y$.

    The above formulas are to be, respectively, interpreted as “$A$ is the domain of $x$", “$B$ is the codomain, or range, of $x$", “$u$ is the composition $x$ followed by $y$", and “$x$ equals $y$"; letters $i, j, k, l, m, ...$ are to be interpreted as “either element, set or class ($C$ ) indices". An example of valid ETAC and ETAS formula is a couple or pair of two letters written as “$(x,y)$"; a more general related example is that of Cartesian or direct products ${\Pi}_{i ~ in ~ C}$.

  2. (S2). There are several composition laws defined in ETAS (as distinct from ETAC where there is only one composition law for each interpretation in any specific type of category ); such multiple composition laws $\Gamma_i$, with $i ~in~ C$ are interpreted as “definitions of multiple (specific) mathematical structures, within the same supercategory $\mathcal{\S}$" .

In the case of general algebras, the multiple composition laws are interpreted as “definitions of algebraic structures", (whereas categorical algebra is interpreted as being “defined by a single composition law ${\Gamma}_1 = \circ $ (or “*" for -involution or $C^*$ -algebras )". An ETAC structure is thus identified by the singleton $\left\{1 \right\}$ index set.

Examples of supercategories

Pseudographs, hypergraphs, 1-categories, categorical algebras, $2$-categories, $n$-categories, functor categories, super-categories, super-diagrams, functor supercatgeories, double groupoids, double categories, organismic supercategories, self-replicating quantum automata, standard Heyting topos, generalized $LM_n$-logic algebra topoi, double algebroids, super-categories of double algebroids, and any higher dimensional algebra (HDA) are examples of supercategories of various orders.

Graphic example of a supercategory

A pictorial representation of a particular class of metagraphs –the class of multigraphs, $M_g$– is also useful as a visual or `geometric' (or topological) representation of a specific example of a supercategory defined over the topological space of the multigraph with the composition operations of the supercategory heteromorphisms defined, in this case of the multigraph, by the concatenations of the multigraph vertices in $n$ dimensions for a finite , $n$-dimensional multigraph that can be graphically rendered on a computer.

Metagraphs and Metacategories

Definition 1.1   A more recent version of Lawvere's axioms was presented by MacLane (2000) in which a metagraph is first defined as a structure consisting of objects $a,b,c,...x,y,z$, arrows $f, g, h, ...$, and two operations– the Domain (which assigns to each arrow $f$ an object $a=dom~ f$), and a Codomain (which assigns to each arrow $f$ an object $b= cod~ f$. Such operations can be readily represented by displaying $f$ as an actual arrow $. \to.$ starting at the $dom ~ f$ and ending at $cod ~ f$, $f: a \to b$. With this pictorial, or `geometric' representation, a finite number of arrows is depicted as a finite graph. Then, one defines a metacategory as a metagraph with two additional operations, Identity and Composition(viz. [12]). Identity assigns to each object $a$ an arrow $id_a = 1_a: a \to a$. A $composition$ operation assigns to each pair of arrows $(f,g)$ with $dom ~g = cod~ f$ an arrow called their composite, $g \circ f : dom~ f \to cod~ g$.

Bibliography

1
I.C. Baianu: 1970, Organismic Supercategories: II. On Multistable Systems. Bulletin of Mathematical Biophysics, 32: 539-561.
2
I.C. Baianu : 1971a, Organismic Supercategories and Qualitative Dynamics of Systems. Bulletin of Mathematical Biophysics, 33 (3), 339–354.
3
I.C. Baianu: 1977, A Logical Model of Genetic Activities in Łukasiewicz Algebras: The Non-linear Theory. Bulletin of Mathematical Biophysics, 39: 249-258.
4
I.C. Baianu: 1980, Natural Transformations of Organismic Structures. Bulletin of Mathematical Biophysics 42: 431-446.
5
I.C. Baianu, Brown R., J. F. Glazebrook, and Georgescu G.: 2006, Complex Nonlinear Biodynamics in Categories, Higher Dimensional Algebra and Łukasiewicz–Moisil Topos: Transformations of Neuronal, Genetic and Neoplastic networks, Axiomathes 16 Nos. 1–2, 65–122.
6
R. Brown R, P.J. Higgins, and R. Sivera.: “Non-Abelian Algebraic Topology”,(vol. 2. in preparation). (2008).
7
R. Brown, J. F. Glazebrook and I. C. Baianu: A categorical and higher dimensional algebra framework for complex systems and spacetime structures, Axiomathes 17:409–493. (2007).
8
R. Brown and C.B. Spencer: Double groupoids and crossed modules, Cahiers Top. Géom.Diff. 17 (1976), 343–362.
9
W.F. Lawvere: 1963. Functorial Semantics of Algebraic Theories. Proc. Natl. Acad. Sci. USA, 50: 869–872
10
W. F. Lawvere: 1966. The Category of Categories as a Foundation for Mathematics. , In Proc. Conf. Categorical Algebra–La Jolla, 1965, Eilenberg, S et al., eds. Springer –Verlag: Berlin, Heidelberg and New York, pp. 1–20.
11
L. Löfgren: 1968. On Axiomatic Explanation of Complete Self–Reproduction. Bull. Math. Biophysics, 30: 317–348.
12
S. Mac Lane. 2000. Ch.1: Axioms for Categories, in Categories for the Working Mathematician. Springer: Berlin, 2nd Edition.



"axiomatic theories of metacategories and supercategories" is owned by bci1.

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See Also: category, hypergraph, topic on axioms, index of algebraic topology

Also defines:  OS, supercategory, metacategory, metagraph
Keywords:  axioms, theory of metacategories, theory of supercategories, organismic supercategories (OS)

Cross-references: graph, topological, representation, double algebroids, topos, quantum automata, organismic supercategories, double categories, double groupoids, super-categories, functor categories, categorical algebra, algebraic structures, type, composition, function, system, supercomputer, hypergraph, computer, concepts, codomain, domain, operations, ETAS axioms, ETAS, composition laws, HDA, higher dimensional algebra, formulas, natural transformations, diagrams, commutative diagrams, identities, objects, morphism, functors, ETAC, elementary theory of abstract categories, categories
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This is version 10 of axiomatic theories of metacategories and supercategories, born on 2010-05-09, modified 2010-05-10.
Object id is 864, canonical name is AxiomaticTheoriesOfMetacategoriesAndSupercategories.
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Physics Classification: 00. (GENERAL)
 02. (Mathematical methods in physics)
 02.70.-cxx (Computational techniques )
 02.90.+p (Other topics in mathematical methods in physics )
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