• relation
  • An incidence structure (P, L, I) consists of a set P whose elements are called points, a disjoint set L whose elements are called lines and an incidence relation I between them, that is, a subset of P × L whose elements are called flags. (wikipedia.org)
  • An incidence structure is a triple (P, L, I) where P is a set whose elements are called points, L is a disjoint set whose elements are called lines and I ⊆ P × L is the incidence relation. (wikipedia.org)
  • Incidence posets have been particularly studied with respect to their order dimension, and its relation to the properties of the underlying graph. (wikipedia.org)
  • The most basic incidence relation is that between a point, P, and a line, l, sometimes denoted P I l. (wikipedia.org)
  • There are many expressions used in common language to describe incidence (for example, a line passes through a point, a point lies in a plane, etc.) but the term "incidence" is preferred because it does not have the additional connotations that these other terms have, and it can be used in a symmetric manner, reflecting this property of the relation. (wikipedia.org)
  • a plane is a set of points) then an incidence relation may be viewed as containment. (wikipedia.org)
  • incident
  • The incidence matrix of an incidence structure C is a p × q matrix B, where p and q are the number of points and lines respectively, such that Bi,j = 1 if the point pi and line Lj are incident and 0 otherwise. (wikipedia.org)
  • An incidence structure is uniform if each line is incident with the same number of points. (wikipedia.org)
  • For instance, a partial linear space is an incidence structure that satisfies: Any two distinct points are incident with at most one common line, and Every line is incident with at least two points. (wikipedia.org)
  • If the first axiom above is replaced by the stronger: Any two distinct points are incident with exactly one common line, the incidence structure is called a linear space. (wikipedia.org)
  • The orientation of the incident light's polarization with respect to the plane of incidence has an important effect on the strength of the reflection. (wikipedia.org)
  • P-polarized light is incident linearly polarized light with polarization direction lying in the plane of incidence. (wikipedia.org)
  • angle
  • In grazing incidence techniques, the X-ray beam impinges on the surface at a very small angle with respect to the surface plane. (warwick.ac.uk)
  • By modifying the incidence angle, the penetration depth of the X-ray beam in the sample can be controlled, and thus, at very shallow angles (typically below 1°), the signal coming from the surface area is maximised. (warwick.ac.uk)
  • Grazing-incidence small-angle scattering ( GISAS ) is a scattering technique used to study nanostructured surfaces and thin films. (wikipedia.org)
  • economics
  • Fiscal incidence is a concept within public finance, a sub-discipline within economics, that refers to the combined overall economic impact of both government taxation and expenditures on the real economic income of individuals. (wikipedia.org)
  • Barna's conceptual framework-first developed as a doctoral candidate at the London School of Economics under Nicholas Kaldor-was influential and today serves as the essential framework for fiscal incidence studies conducted by the British government. (wikipedia.org)
  • In economics, tax incidence or tax burden is the analysis of the effect of a particular tax on the distribution of economic welfare. (wikipedia.org)
  • taxation
  • When the economic incidence of taxation is combined with the economic incidence of government expenditures, the result is a measure of the overall increase or decrease in welfare that individuals enjoy from the state's taxing and spending policies. (wikipedia.org)
  • The concept was brought to attention by the French Physiocrats, in particular François Quesnay, who argued that the incidence of all taxation falls ultimately on landowners and is at the expense of land rent. (wikipedia.org)
  • typically
  • The concept of an incidence structure is very simple and has arisen in several disciplines, each introducing its own vocabulary and specifying the types of questions that are typically asked about these structures. (wikipedia.org)
  • When the tax incidence falls on the farmer, this burden will typically flow back to owners of the relevant factors of production, including agricultural land and employee wages. (wikipedia.org)
  • refers
  • The 'incidence' of pediatric dysphagia refers to the number of new cases identified in a specified time period. (asha.org)
  • proportion
  • Where the period of time considered is an entire lifetime, the incidence proportion is called lifetime risk. (wikipedia.org)
  • It is sometimes also referred to as the incidence proportion. (wikipedia.org)
  • For example, if a population initially contains 1,000 non-diseased persons and 28 develop a condition over two years of observation, the incidence proportion is 28 cases per 1,000 persons per two years, i.e. 2.8% per two years. (wikipedia.org)
  • In the same example as above, the incidence rate is 14 cases per 1000 person-years, because the incidence proportion (28 per 1,000) is divided by the number of years (two). (wikipedia.org)
  • structures
  • It sometimes happens that authors blur the distinction between a study and the objects of that study, so it is not surprising to find that some authors refer to incidence structures as incidence geometries. (wikipedia.org)
  • Very general incidence structures can be obtained by imposing "mild" conditions, such as: A partial linear space is an incidence structure for which the following axioms are true: Every pair of distinct points determines at most one line. (wikipedia.org)
  • Incidence structures are most often considered in the geometrical context where they are abstracted from, and hence generalize, planes (such as affine, projective, and Möbius planes), but the concept is very broad and not limited to geometric settings. (wikipedia.org)
  • Incidence structures of this type are called set-theoretic. (wikipedia.org)
  • Incidence structures use a geometric terminology, but in graph theoretic terms they are called hypergraphs and in design theoretic terms they are called block designs. (wikipedia.org)
  • relatively
  • The incidence of open marriage has remained relatively stable over the last two generations. (wikipedia.org)
  • The incidence of toxic shock syndrome rose significantly in the following decade until it reached a peak in the 1980s and declined from that point until today and is now seen as a relatively rare condition. (news-medical.net)
  • implies
  • Use of this measure implies the assumption that the incidence rate is constant over different periods of time, such that for an incidence rate of 14 per 1000 persons-years, 14 cases would be expected for 1000 persons observed for 1 year or 50 persons observed for 20 years. (wikipedia.org)
  • 1993
  • The concept of incidence coloring was introduced by Brualdi and Massey in 1993. (wikipedia.org)
  • This report summarizes provisional 2006 TB incidence data from the National TB Surveillance System and describes trends since 1993. (cdc.gov)
  • optics
  • In describing reflection and refraction in optics, the plane of incidence (also called the meridional plane[citation needed]) is the plane which contains the surface normal and the propagation vector of the incoming radiation. (wikipedia.org)
  • interval
  • The interval incidence coloring number of G is the minimum number of colors used for the interval incidence coloring of G. It is denoted by IIC(G). If only IIC(G) colors are used for the interval incidence coloring, then it is said to be minimal. (wikipedia.org)
  • wings
  • Early types incorporating one or more variable-incidence wings included the Zerbe Air Sedan, a tandem quadruplane of 1919, and the tandem-wing Flying Flea which was popular during the 1930s. (wikipedia.org)
  • Largely
  • This public health initiative is largely to account for the decrease in incidence of toxic shock syndrome since the 1980s and its relative rarity today. (news-medical.net)
  • equivalent
  • It is equivalent to the incidence, calculated using a period of time during which all of the individuals in the population are considered to be at risk for the outcome. (wikipedia.org)
  • variable
  • An early patent for the variable-incidence wing was lodged in France on 20 May 1912 by Bulgarian inventor George Boginoff. (wikipedia.org)
  • Without a variable-incidence wing (or other high-lift device), the pilot must pitch up the entire aircraft to maintain lift at the slow approach speed required, and this can restrict forward vision. (wikipedia.org)
  • One of the earlier designs to have variable incidence for this purpose was the Supermarine Type 322 prototype carrier-borne aircraft of 1943. (wikipedia.org)
  • The only production aircraft to incorporate variable incidence was the American F-8 Crusader carrier-borne jet fighter, while other prototype designs to have flown include the Martin XB-51. (wikipedia.org)
  • these are called variable incidence wing s. (britannica.com)
  • data
  • An incidence structure is what is obtained when all other concepts are removed and all that remains is the data about which points lie on which lines. (wikipedia.org)
  • Data from research conducted over the period from 2000-2006, reported that the incidence of toxic shock syndrome now remains low and stable. (news-medical.net)
  • Determining the overall incidence of anterior cruciate ligament injury in the general population is difficult given the limited availability of accurate data. (humankinetics.com)
  • known
  • When the denominator is the sum of the person-time of the at risk population, it is also known as the incidence density rate or person-time incidence rate. (wikipedia.org)
  • To gain perspective on the extent of this problem, we will review what is known in regard to injury incidence in the general population, within sports, between sexes, and across age groups. (humankinetics.com)
  • case
  • This conjecture was disproved by Guiduli, who showed that incidence coloring concept is a directed star arboricity case, introduced by Alon and Algor. (wikipedia.org)
  • He showed that in case of outerplanar graph of maximum degree 4, the incidence chromatic number is not 5. (wikipedia.org)
  • concept
  • There is no natural concept of distance (a metric) in an incidence structure. (wikipedia.org)
  • The key concept is that the tax incidence or tax burden does not depend on where the revenue is collected, but on the price elasticity of demand and price elasticity of supply. (wikipedia.org)
  • measure
  • To measure incidence you must take into account how many years each person contributed to the study, and when they developed HIV. (wikipedia.org)
  • structure
  • Another way to define a distance again uses a graph-theoretic notion in a related structure, this time the collinearity graph of the incidence structure. (wikipedia.org)
  • The distance between two points of the incidence structure can then be defined as their distance in the collinearity graph. (wikipedia.org)
  • When distance is considered in an incidence structure, it is necessary to mention how it is being defined. (wikipedia.org)
  • This is an incidence structure in which the lines fall into k parallel classes, so that two lines in the same parallel class have no common points, but two lines in different classes have exactly one common point, and each point belongs to exactly one line from each parallel class. (wikipedia.org)
  • The Fano plane above is a self-dual incidence structure. (wikipedia.org)
  • As an incidence structure, X is the set of points and F is the set of lines, usually called blocks in this context (repeated blocks must have distinct names, so F is actually a set and not a multiset). (wikipedia.org)
  • cases
  • However, it could equally well be argued that in some cases the incidence of the tax falls on the employer. (wikipedia.org)
  • In 2006, TB incidence rates in the 51 reporting areas ranged from 0.8 (Wyoming) to 12.6 (DC) cases per 100,000 population (median: 3.4 cases). (cdc.gov)
  • particular
  • Some particular population groups, such as women aged between 13 and 25 years, were more likely to be affected by the syndrome, with an incidence of 1.41 per 100,000. (news-medical.net)
  • Order
  • Researchers need clear definitions of open marriage in order to accurately estimate the incidence of open marriage. (wikipedia.org)
  • types
  • In these types, varying the incidence of one wing while leaving another fixed was used as a substitute for the more conventional elevator control surface. (wikipedia.org)