List of undecidable problems. Problems in logic Problems about abstract machines The mortal matrix problem: determining, given a finite set of n × n matrices with integer entries, whether they can be multiplied in some order, possibly with repetition, to yield the zero matrix.
(This is known undecidable for a set of 7 or more 3 × 3 matrices, or a set of two 21 × 21 matrices.)Determining whether a finite set of upper triangular 3 × 3 matrices with nonnegative integer entries generates a free semigroup.Determining whether two finitely generated subsemigroups of Mn(Z) have a common element. Problems in combinatorial group theory Problems in topology Determining whether two finite simplicial complexes are homeomorphic.Determining whether a finite simplicial complex is (homeomorphic to) a manifold.Determining whether the fundamental group of a finite simplicial complex is trivial. Error 403. Empire - Kostüme Kleidung Mode nach Maß - Werkstatt Gandiva. Foucault_archiv. The Travels Of Scarmentado by Voltaire.
Freud - Psychoanalyse: Notiz über den »Wunderblock« Wenn ich meinem Gedächtnis mißtraue — der Neurotiker tut dies bekanntlich in auffälligem Ausmaße, aber auch der Normale hat allen Grund dazu —, so kann ich dessen Funktion ergänzen und versichern, indem ich mir eine schriftliche Aufzeichnung mache.
Die Fläche, welche diese Aufzeichnung bewahrt, die Schreibtafel oder das Blatt Papier, ist dann gleichsam ein materialisiertes Stück des Erinnerungsapparates, den ich sonst unsichtbar in mir trage. Wenn ich mir nur den Ort merke, an dem die so fixierte »Erinnerung« untergebracht ist, so kann ich sie jederzeit nach Belieben »reproduzieren« und bin sicher, daß sie unverändert geblieben, also den Entstellungen entgangen ist, die sie vielleicht in meinem Gedächtnis erfahren hätte.
Wenn ich mich dieser Technik zur Verbesserung meiner Gedächtnisfunktion in ausgiebiger Weise bedienen will, bemerke ich, daß mir zwei verschiedene Verfahren zu Gebote stehen. Die Analogie hätte nicht viel Wert, wenn sie sich nicht weiter verfolgen ließe.
Voltaire - Scarmentado. Ludwig Tieck. Hugo von Hoffmansthal - 672. Nacht. Sacred Texts Timeline. Sacred-textsSacred Time Origins of World Religions This is a timeline which gives the history of sacred texts, as well as a few other relevant events.
Of course, not all of the dates in this timeline are accurate; some are entirely conjectural. I have included a few dates, events and documents which are or may be entirely fictional. Links on this page are to resources at this site, not to external sites. I welcome feedback about any errors of fact in this timeline. Diogenes Laertius. Augustinus - Confessiones. Memories of the East Village Art Scene. In a strictly hedonistic way, Eileen’s Reno Bar was integral to the East Village community.
A narrow pocket of surrealism on Second Avenue between 11th and 12th, its ceiling surfaced in plastic jade plant—brown plastic jade plant—Eileen’s had its flaccid nights of dead-room tone. But most evenings brought a steady influx of pre-op transsexuals, clueless walk-ins, bisexual drug dealers, garrulous drunks with a schizophrenic flair, Ricardo Montalban types from Europe lusting after chicks with dicks, and a few black-humored fags like myself, who much preferred the Reno Bar’s nightly Halloween party to clocking the aging process in some drippy gay bar.
Eileen’s had the carnal whoop-de-do of a fetish convention. It was also full of crack whores working the track on 11th Street. Ball and socket joint. The ball and socket joint (or spheroidal joint) is a joint in which the ball-shaped surface of one rounded bone fits into the cup-like depression of another bone.
The distal bone is capable of motion around an indefinite number of axes, which have one common center. It enables the bone to move in many planes (almost all directions). An enarthrosis is a special kind of spheroidal joint in which the socket covers the sphere beyond its equator. Examples Examples of this form of articulation are found in the hip, where the rounded head of the femur (ball) rests in the cup-like acetabulum (socket) of the pelvis, and in the glenohumeral joint of the shoulder, where the rounded head of the humerus (ball) rests in the cup-like glenoid fossa (socket) of the shoulder blade. It should be noted that the shoulder includes a Sternoclavicular articulation joint.
References This article incorporates text from a public domain edition of Gray's Anatomy. Human skeletal changes due to bipedalism.  Hip Knee
Lessons. A comparison of the Chimp, Human, and A. afarensis femur demonstrates a rounder femoral head and longer femoral neck length in bipeds.
The femur is a critical link between the pelvis, vertebral column, and the feet in a biped because all of the body's mass is transferred to the feet via this bone during standing and movement. The gluteal muscles that link the femur to the pelvis provide the propulsive force for locomotion. The rounded femoral head articulates with the pelvis at the acetabulum (hip joint). The femoral shaft is generally straight, ending in two bulbous condyles. These are larger and more elliptical in bipeds compared to the relatively smaller and rounder condyles seen in quadrupeds. DER SPIEGEL 14/1966 - JESUS UND DIE KIRCHEN. Meine Herren, es wackelt alles!
Birth–death process. The birth–death process is a special case of continuous-time Markov process where the state transitions are of only two types: "births", which increase the state variable by one and "deaths", which decrease the state by one.
The model's name comes from a common application, the use of such models to represent the current size of a population where the transitions are literal births and deaths. Birth–death processes have many applications in demography, queueing theory, performance engineering, epidemiology or in biology. They may be used, for example to study the evolution of bacteria, the number of people with a disease within a population, or the number of customers in line at the supermarket. When a birth occurs, the process goes from state n to n + 1. Monte Carlo method. Monte Carlo methods (or Monte Carlo experiments) are a broad class of computational algorithms that rely on repeated random sampling to obtain numerical results; typically one runs simulations many times over in order to obtain the distribution of an unknown probabilistic entity.
They are often used in physical and mathematical problems and are most useful when it is difficult or impossible to obtain a closed-form expression, or infeasible to apply a deterministic algorithm. Monte Carlo methods are mainly used in three distinct problem classes: optimization, numerical integration and generation of draws from a probability distribution.
Astronomers discover complex organic matter exists throughout the universe. Random walk. Example of eight random walks in one dimension starting at 0. The plot shows the current position on the line (vertical axis) versus the time steps (horizontal axis). A random walk is a mathematical formalization of a path that consists of a succession of random steps. For example, the path traced by a molecule as it travels in a liquid or a gas, the search path of a foraging animal, the price of a fluctuating stock and the financial status of a gambler can all be modeled as random walks, although they may not be truly random in reality. The term random walk was first introduced by Karl Pearson in 1905. Random walks have been used in many fields: ecology, economics, psychology, computer science, physics, chemistry, and biology. Random walks explain the observed behaviors of processes in these fields, and thus serve as a fundamental model for the recorded stochastic activity.
Markov process. Markov process example Introduction This undated image provided by the journal Science a picokeystone, extracted from an aerogel tile from the Stardust interstellar dust collector. Scientists said seven microscopic particles collected by NASA's comet-chasing spacecraft, Stardust, appear to. Espace Toutes les photos de l'espace, frontière de l'infini. Vista galleria:Espace 1 - 16 di 30 Prec.Succ. 1 di 30 foto previous. Special relativity. Special relativity implies a wide range of consequences, which have been experimentally verified, including length contraction, time dilation, relativistic mass, mass–energy equivalence, a universal speed limit, and relativity of simultaneity. It has replaced the conventional notion of an absolute universal time with the notion of a time that is dependent on reference frame and spatial position. Rather than an invariant time interval between two events, there is an invariant spacetime interval.
Relativistic Doppler effect. Diagram 1. A source of light waves moving to the right, relative to observers, with velocity 0.7c. The frequency is higher for observers on the right, and lower for observers on the left. Maxwell's equations. Kennedy–Thorndike experiment. Figure 1. Ives–Stilwell experiment. Ives–Stilwell experiment (1938). Michelson–Morley experiment. Figure 1. Michelson and Morley's interferometric setup, mounted on a stone slab and floating in a pool of mercury. Cahier physique - physics workbook. PART I click here (from Copernicus to Newton) Time dilation of moving particles. Biologist warn of early stages of Earth's sixth mass extinction event. Lists of unsolved problems. Why Probability in Quantum Mechanics is Given by the Wave Function Squared.
One of the most profound and mysterious principles in all of physics is the Born Rule, named after Max Born. In quantum mechanics, particles don’t have classical properties like “position” or “momentum”; rather, there is a wave function that assigns a (complex) number, called the “amplitude,” to each possible measurement outcome. The Born Rule is then very simple: it says that the probability of obtaining any possible measurement outcome is equal to the square of the corresponding amplitude. Library - Google Search. History of writing. Why study things? - An introduction to material culture. Oulipo.
How Your Brain Can Control Time. Optische Täuschungen - SPIEGEL ONLINE - Nachrichten. Panspermia. Near-Earth object. Humanzee. Pleiades. Schiefer. Erinyen. Proper motion. Universal Time. List of common misconceptions. William James Sidis. Seclusion. Ancient astronauts. Out-of-place artifact.