A generalization of cohens theorem

Ngày tải lên: 05/08/2014, 15:20

... trees, and then the parser will halt The essential properties of offline parable grammars are these: Theorem It is decidable whether a given unification grammar is offline parsable Proof: It is ... unifier of An and A' (after suitable renaming of variables) Then the set of ground instances of lists in D n is the set of chain derivations of length n in the ground...

Ngày tải lên: 21/02/2014, 20:20

Ngày tải lên: 05/08/2014, 15:20

... Pk,l ]p,q forms the bibasic factorial factor of P of maximal length k Iterating this procedure one gets a factorization of P in terms of “greatest” factorial factors Definition We say that P1 , ... [Pk ]p,q p,q Proof Due to the choice of the bibasic shift operator , the proof of the so-called Fundamental qGFF Lemma (cf Paule and Riese [9, Lemma 1]) can be carried over to the bi...

Ngày tải lên: 07/08/2014, 06:20

... Generalization of the Braid Arrangement The classical braid arrangement An in complex n-space is given by the “thick” diagonals Hij : zi = zj for ≤ i < j ≤ n The braid arrangement, also known as the ... coordinates and leaving Acol,s invariant n By a calculation of the character of Sn on the homology of the order complex of LAcol,s n and using a formu...

Ngày tải lên: 07/08/2014, 06:20

... 1, and thus provide another proof of the totally symmetric self-complementary plane partitions conjecture However, there is even a two-parameter generalization of (5.2), (namely the determinant ... research process it was the other way round This proof was found first and provided (some of) the inspiration for the later proofs of Theorems and Step An equivale...

Ngày tải lên: 07/08/2014, 06:20

... n and in the particular case of R induced by an injective mapping, Theorem improves Theorem To deal with the generalization of the most important and most difficult case of Theorem — that of small ... 0.80 The proofs of Theorems 1–4 are mostly combinatorial, with a somewhat surprising interference of graph theory in the proof of Theorem — see also Section 4, the...

Ngày tải lên: 07/08/2014, 06:20

... 6, 10, 7) As discussed in the proof of Proposition 2, the equality of the diagram squares of rank at most m − for π and σ = Φm (π) means that σi = πi for all i for which there exist at most m ... (i, j) ∈ Om (π) Proof For any m ≥ 2, let D be the set of all diagram squares of rank at most m − The proof is based on the following procedure First represent the elements of D as...

Ngày tải lên: 07/08/2014, 07:21

... union of d subgraphs, each of which is k-colorable In particular, all graphs in Bd are 2d -colorable We show that this bound is sharp, which is somewhat surprising since Cartesian products of bipartite ... “Combinatorial Challenges” held in DIMACS in April 2006; we thank the DIMACS center for its hospitality We also thank Stephen Hartke and Hemanshu Kaul for participating in livel...

Ngày tải lên: 07/08/2014, 21:21

... isomorphism properties of generalized Paley graphs In this paper we use this tool to study cyclic graphs of non-prime order and give a new generalization of generalized Paley graphs, which we will ... lower bounds R(3, 3) and R(4, 4) 18 These graphs were Paley graphs, and the same method produced results such like R(6, 6) 102 [6] and R(8, 8) 282 [2] I...

Ngày tải lên: 08/08/2014, 11:20

... sum of labels over the the electronic journal of combinatorics 17 (2010), #N32 set N(u) of all neighbors of u in G The function c is called a lucky labeling of G if S(u) = S(w) for every pair of ... 1078-1081 [3] O Kouba, A duality based proof of the Combinatorial Nullstellensatz, Electron J Combin 16 (2009), Note 9, pp [4] M Michalek, A short proof of Combinatorial Nullst...

Ngày tải lên: 08/08/2014, 11:20

... similar argument that every x ∈ X has at most m neighbors in A A By an escaping pair we mean a pair (x, y) of vertices with x ∈ X and y ∈ Ns (x) We call x the head and y the tail of the pair By the ... escaping paths Since there are c cops in the game, the cops control at most 3msds c escaping paths By controlling each escaping path, the cops can decrease the...

Ngày tải lên: 08/08/2014, 12:23

... –linear set L(S) of P = P G(V, Fq3 ) of rank having a unique point P of weight (and hence a unique plane π of P of weight 5) and each other point of weight Moreover, if one of the following additional ... semifield S of F3 is of type (i, j), then the transpose semifield St of S is of type (i, j) as well Proof It follows from previous arguments and from Proposition 2.3 the...

Ngày tải lên: 08/08/2014, 12:23

... counterexamples that are the line graph of a multigraph for ∆(G) ≥ This is tight since the above counterexample for ∆(G) = is a line graph of a multigraph Theorem If G is the line graph of a multigraph with ... χ(G) ≤ ω(G)+∆(G)+1 holds for all graphs G For further information about Reed’s conjecture, see King’s thesis [11] and King and Reed’s proof of the conjecture f...

Ngày tải lên: 08/08/2014, 14:23

... that arctan(k/n) ϕ(k) = k(n + k) π arctan x dx 1+x arctan x 1+x dx The 1−t 1+t to obtain Thus we only need to evaluate the integral I = to this is to make the change of variables x ← I= arctan = ... U131, Mathematical Reflections (4) (2009) [2] G H Hardy and E M.Wright, An Introduction to the Theory of Numbers (5th ed.), Oxford University Press (1980) Omran Kouba Department of Mathem...

Ngày tải lên: 15/08/2014, 16:55