We introduce two new notions for hypergraphs, hypertree-depth and minors in hypergraphs. We characterise hypergraphs of bounded hypertree-depth by the ultramonotone robber and marshals game, by vertex-hyperrankings and by centred hypercolourings. Furthermore, we show that minors in hypergraphs are ‘well-behaved’ with respect to hypertree-depth and other hypergraph invariants, such as generalise...

Article history: Received 19 May 2011 Available online xxxx

Consider two locally finite rooted trees as equivalent if each of them is a topological minor of the other, with an embedding preserving the tree-order. Answering a question of van der Holst, we prove that there are uncountably many equivalence classes.

It is proved that there are functions f (r) and N(r, s) such that for every positive integer r , s, each graph G with average degree d(G) = 2|E(G)|/|V (G)| ≥ f (r), and with at least N(r, s) vertices has a minor isomorphic to Kr,s or to the union of s disjoint copies of Kr . © 2005 Published by Elsevier Ltd

head trauma is the most common form of accidental injury among children, which is a source of concern for parents and pediatricians. after head trauma, children may be loss of intellectual function. most head trauma in children is minor and not related with brain injury or long-term outcome. however, a small number of children may have a clinically important traumatic brain injury. the incidenc...

background :highserum level of cancer antigen 15.3 (ca15.3) has been reported in some malignant and nonmalignant conditions including thalassemia major which could have been resulted from ineffective erythropoiesis. we aimed to evaluate the serum level of ca15.3 in carriers of beta-thalassemia by comparing them with cancer patients and healthy individuals.   methods : this cross-sectional study...

pneumococcal autolysins are enzymes involved in cell wall turnover and cellular division physiologically. they have been found to be involved in the pneumococcus pathogenesis. the aim of this study was to identify the autolytic activity of spr1754 as a novel protein of streptococcus pneumoniae . moreover, the binding of the recombinant protein to plasma proteins was also determined. the spr1754...