scholarly journals BRANCH GROUPS, ORBIT GROWTH, AND SUBGROUP GROWTH TYPES FOR PRO- GROUPS

2020 ◽  
Vol 8 ◽  
Author(s):  
YIFTACH BARNEA ◽  
JAN-CHRISTOPH SCHLAGE-PUCHTA

In their book Subgroup Growth, Lubotzky and Segal asked: What are the possible types of subgroup growth of the pro- $p$ group? In this paper, we construct certain extensions of the Grigorchuk group and the Gupta–Sidki groups, which have all possible types of subgroup growth between $n^{(\log n)^{2}}$ and $e^{n}$ . Thus, we give an almost complete answer to Lubotzky and Segal’s question. In addition, we show that a class of pro- $p$ branch groups, including the Grigorchuk group and the Gupta–Sidki groups, all have subgroup growth type $n^{\log n}$ .

Weed Science ◽  
2021 ◽  
pp. 1-35
Author(s):  
John A. Schramski ◽  
Christy L. Sprague ◽  
Eric L. Patterson

Abstract Horseweed [Conyza canadensis (L.) Cronquist] is a facultative winter annual weed that can emerge from March to November in Michigan. Fall emerging C. canadensis overwinters as a rosette, while spring emerging C. canadensis skips the rosette stage and immediately grows upright upon emergence. In Michigan, primary emergence recently shifted from fall to spring/summer and therefore from a rosette to an upright growth type. Growth chamber experiments were conducted to determine 1) whether both C. canadensis growth types could originate from a single parent and 2) if common environmental cues can influence growth type. Variations in temperature, photoperiod, competition, shading, and soil moisture only resulted in the rosette growth type in four C. canadensis populations originating from seed collected from a single parent of the upright growth type. However, a vernalization period of four weeks following water imbibition, but prior to germination, resulted in the upright growth type. Dose-response experiments were conducted to determine whether glyphosate sensitivity differed between C. canadensis growth types generated from a single parent of the upright growth type. Upright type C. canadensis from known glyphosate-resistant populations ISB-18 and MSU-18 were four and three-fold less sensitive to glyphosate than their rosette siblings, respectively. Interestingly, differences in glyphosate sensitivity was not observed between growth types from the susceptible population. These results suggest that while C. canadensis populations shift from winter to summer annual lifecycles, concurrent increases in glyphosate resistance could occur.


2004 ◽  
Vol 21 (3) ◽  
pp. 164-165
Author(s):  
John R. Brooks ◽  
Harry V. Wiant

Abstract Zeide's (1993) two-point method for projecting volume growth was used to compare the predicted volume to a current intensive inventory of an Appalachian hardwood forest in northern West Virginia. Results indicate that the calculated growth type was stable and that the 8-year predicted volume was within 2% of the inventory estimate. North. J. Appl. For. 21(3):164–165.


1969 ◽  
Vol 49 (6) ◽  
pp. 765-768 ◽  
Author(s):  
K. O. Lapins

Two-year-old apple seedlings of six progenies resulting from crosses between cultivars of standard growth or their compact mutants were classified for standard or compact growth type. A natural compact mutant of McIntosh (Wijcik) in combination with Golden Delicious transmitted compact growth habit to 43.9% of its progeny, whereas the radiation-induced compact mutant of McIntosh (8F-2-27), in the same combination did not transmit this characteristic. Number of side shoots, internodal length, and the ratio of length to diameter of one-year-old shoots were useful characteristics in distinguishing between the standard and compact growth types in two-year-old seedling trees. As the segregation of seedlings of compact growth habit is of great interest both from theoretical and practical aspects, a careful assessment of the transmissibility of compactness by mutant and non-mutated cultivars in various cross-combinations is suggested.


2020 ◽  
Vol 23 (1) ◽  
pp. 1-15
Author(s):  
Yiftach Barnea ◽  
Jan-Christoph Schlage-Puchta

AbstractThe fastest normal subgroup growth type of a finitely generated group is {n^{\log n}}. Very little is known about groups with this type of growth. In particular, the following is a long standing problem: Let Γ be a group and Δ a subgroup of finite index. Suppose Δ has normal subgroup growth of type {n^{\log n}}. Does Γ have normal subgroup growth of type {n^{\log n}}? We give a positive answer in some cases, generalizing a result of Müller and the second author and a result of Gerdau. For instance, suppose G is a profinite group and H an open subgroup of G. We show that if H is a generalized Golod–Shafarevich group, then G has normal subgroup growth of type {n^{\log n}}. We also use our methods to show that one can find a group with characteristic subgroup growth of type {n^{\log n}}.


2011 ◽  
Vol 39 (No. 3) ◽  
pp. 73-83 ◽  
Author(s):  
O. Horňáková ◽  
M. Závodná ◽  
M. Žáková ◽  
J. Kraic ◽  
F. Debre

The study of diversity in common bean was based on morphological and agronomical characteristics, differentiation of collected accessions by morphological and molecular markers, detection of genetic variation, and duplicates detection in bean landraces. The analysed 82 accessions of common bean (Phaseolus vulgaris L.) were collected in the Western andEastern Carpatien as landrace mixtures. Their seeds were segregated and pooled according to their characteristics; they were further multiplicated, and introduced into the collection. An extensive variation in plant and seed traits was discovered in thirty-three morphological and agronomical characteristics. Nevertheless, some of the accessions were identical in these characteristics. Cluster analysis grouped genotypes into two main branches, reflecting the growth type, seed size parameters, and thousand-seed weight. Molecular differentiation studies were performed by multilocus polymorphism detection in microsatellite and minisatellite DNA regions. Cluster analysis based on molecular data also grouped genotypes but no linkage to morphological traits was revealed. Bean accessions with very similar or identical morphological characters were clearly distinguished by DNA banding patterns. The presence of duplicates was excluded.  


2021 ◽  
Vol 37 (3) ◽  
pp. 839-866
Author(s):  
Wei Zheng ◽  
Hajo Broersma ◽  
Ligong Wang

AbstractMotivated by several conjectures due to Nikoghosyan, in a recent article due to Li et al., the aim was to characterize all possible graphs H such that every 1-tough H-free graph is hamiltonian. The almost complete answer was given there by the conclusion that every proper induced subgraph H of $$K_1\cup P_4$$ K 1 ∪ P 4 can act as a forbidden subgraph to ensure that every 1-tough H-free graph is hamiltonian, and that there is no other forbidden subgraph with this property, except possibly for the graph $$K_1\cup P_4$$ K 1 ∪ P 4 itself. The hamiltonicity of 1-tough $$K_1\cup P_4$$ K 1 ∪ P 4 -free graphs, as conjectured by Nikoghosyan, was left there as an open case. In this paper, we consider the stronger property of pancyclicity under the same condition. We find that the results are completely analogous to the hamiltonian case: every graph H such that any 1-tough H-free graph is hamiltonian also ensures that every 1-tough H-free graph is pancyclic, except for a few specific classes of graphs. Moreover, there is no other forbidden subgraph having this property. With respect to the open case for hamiltonicity of 1-tough $$K_1\cup P_4$$ K 1 ∪ P 4 -free graphs we give infinite families of graphs that are not pancyclic.


Author(s):  
Francesco de Giovanni ◽  
Marco Trombetti

AbstractLet $${\mathfrak {X}}$$ X be a group class. A group G is an opponent of $${\mathfrak {X}}$$ X if it is not an $${\mathfrak {X}}$$ X -group, but all its proper subgroups belong to $${\mathfrak {X}}$$ X . Of course, every opponent of $${\mathfrak {X}}$$ X is a cohopfian group and the aim of this paper is to describe the smallest group class containing $${\mathfrak {X}}$$ X and admitting no such a kind of cohopfian groups.


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