Higman's theorem
WebHigman's embedding theorem also implies the Novikov-Boone theorem (originally proved in the 1950s by other methods) about the existence of a finitely presented group with algorithmically undecidable word problem. Indeed, it is fairly easy to construct a finitely generated recursively presented group with undecidable word problem. WebGraham Higman, 1987 CONTENTS 1. Introduction 1 1.1. The main steps of Higman’s proof 2 1.2. Comparison of the current modification with [11] 2 1.3. Other proofs for Higman’s …
Higman's theorem
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WebYerevan State University Abstract We suggest a modified and briefer version for the proof of Higman's embedding theorem stating that a finitely generated group can be embedded in a finitely... WebAbstract For a quasi variety of algebras K, the Higman Theorem is said to be true if every recursively presented K-algebra is embeddable into a finitely presented K-algebra; the …
WebFeb 12, 2016 · By Higman's lemma, the subword order on A ∗ is a well-quasi-order. Therefore, for each language L, the set F of minimal words of L (for the subword ordering) is a finite set F and ш ш L ш A ∗ = F ш A ∗. It is now easy to show that ш F ш A ∗ is a regular language. In a vein similar to Pin's answer. WebApr 4, 2006 · THE HIGMAN THEOREM. People often forget that Graham Higman proved what really amounts to labeled Kruskal's Theorem (bounded valence) EARLIER than Kruskal! G. Higman, Ordering by divisibility in abstract algebras, Proc. London Math. Soc. (3), 2:326--336, 1952. Since this Higman Theorem corresponds to LKT (bounded valence), we know …
Webgraph. A rst veri cation that the given graph is the Higman-Sims graph is given as Theorem 1 whose proof is left as an exercise. Section 4 introduces some of the auto-morphisms of the graph which can be used to show that the Higman-Sims graph is in fact a Cayley graph. These automorphisms also give a hint of the remarkable symme-tries of this ... WebS1. Introduction. Our work is based on a remarkable theorem of Higman [22],1 given below as Theorem 1.3. Convention: is a nite alphabet. Definition 1.1. Let x;y2 . We say that xis a subsequence of yif x= x 1 x nand y2 x 1 x 2 x n 1 x n. We denote this by x y. Notation 1.2. If Ais a set of strings, then SUBSEQ(A) is the set of subse-quences of ...
WebWe believe that Theorem 1.2 can in principle be extended to n 18 by building upon our approach, and parallelizing the computation (see x7.6). It is unlikely however, that this would lead to a disproof of Higman’s Conjecture 1.1 without a new approach. Curiously, this brings the status of Higman’s conjecture in line with that of Higman’s
Webthe Higman–Haines sets in terms of nondeterministic finite automata. c 2007 Published by Elsevier B.V. Keywords: Finite automata; Higman’s theorem; Well-partial order; Descriptional complexity; Non-recursive trade-offs 1. Introduction A not so well-known theorem in formal language theory is that of Higman [6, Theorem 4.4], which reads as ... circulating societyWebOct 1, 1990 · The Nagata-Higman theorem for the nilpotency of nil algebras of bounded index was proved in 1953 by Nagata [Nal] over a field of characteristic 0 and then in 1956 … diamond head hawaii camhttp://math.columbia.edu/~martinez/Notes/hindmantheorem.pdf circulating rn responsibilitiesWebTheorem 1.3 (Higman [22]). If Ais any language over , then SUBSEQ(A) is regular. In fact, for any language Athere is a unique minimum (and nite) set Sof strings such that (1) … diamond head hawaii busWeba modified proof for higman’s embedding theorem 3 Solving Hilbert’s T enth Problem [ 13 ] established that a subset of Z n is recursively enumer- able if and only if it is Diophantine. diamond head hawaii eruptingWebCiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Given two strings x, y ∈ Σ ∗ , say that x is a subsequence of y (denoted x ≼ y) if x results from removing zero or more characters from y. For a language L ⊆ Σ ∗ , define SUBSEQ(L) to be the set of all subsequences of strings in L. We give a new proof of a result of Higman, which states, If L … circulating story crossword clueWebclassical result states that Higman’s lemma is equivalent to an abstract set existence principle known as arithmetical comprehension, over the weak base theory RCA0 (see [15, Theorem X.3.22]). Question 24 from a well-known list of A. Montalb´an [11] asks about the precise strength of Nash-Williams’ theorem. The latter is known circulating sensation crossword