A stock market bubble is a type of economic bubble taking place in stock markets when market participants drive stock prices above their value in relation to some system of stock valuation. Behavioral finance theory attributes stock market bubbles to cognitive biases that lead to groupthink and herd behavior. Bubbles occur not only in real-world markets, with their inherent uncertainty and noise, but in predictable experimental markets. In the laboratory, uncertainty is eliminated and calculating the expected returns should be a simple mathematical exercise, because participants are endowed with assets that are defined to have a finite lifespan and a known probability distribution of dividends. Other theoretical explanations of stock market bubbles have suggested that they are rational and contagious. Early stock market bubbles and crashes have their roots in financial activities of the 17th-century Dutch Republic, the birthplace of the first formal stock exchange and market in history; the Dutch tulip mania, of the 1630s, is considered the world's first recorded speculative bubble.

Two famous early stock market bubbles were the Mississippi Scheme in France and the South Sea bubble in England. Both bubbles came to an abrupt end in 1720; those stories, many others, are recounted in Charles Mackay's 1841 popular account, "Extraordinary Popular Delusions and the Madness of Crowds". The two most famous bubbles of the twentieth century, the bubble in American stocks in the 1920s just before the Wall Street Crash of 1929 and the following Great Depression, the Dot-com bubble of the late 1990s, were based on speculative activity surrounding the development of new technologies; the 1920s saw the widespread introduction of an amazing range of technological innovations including radio, automobiles and the deployment of electrical power grids. The 1990s was the decade when e-commerce technologies emerged. Other stock market bubbles of note include the Encilhamento occurred in Brazil during the late 1880s and early 1890s, the Nifty Fifty stocks in the early 1970s, Taiwanese stocks in 1987–89 and Japanese stocks in the late 1980s.

Stock market bubbles produce hot markets in initial public offerings, since investment bankers and their clients see opportunities to float new stock issues at inflated prices. These hot IPO markets misallocate investment funds to areas dictated by speculative trends, rather than to enterprises generating longstanding economic value; when there is an over abundance of IPOs in a bubble market, a large portion of the IPO companies fail never achieve what is promised to the investors, or can be vehicles for fraud. Emotional and cognitive biases seem to be the causes of bubbles, but when the phenomenon appears, pundits try to find a rationale, so as not to be against the crowd. Thus, people will dismiss concerns about overpriced markets by citing a new economy where the old stock valuation rules may no longer apply; this type of thinking helps to further propagate the bubble whereby everyone is investing with the intent of finding a greater fool. Still, some analysts cite the wisdom of crowds and say that price movements do reflect rational expectations of fundamental returns.

Large traders become powerful enough to rock the boat. To sort out the competing claims between behavioral finance and efficient markets theorists, observers need to find bubbles that occur when a available measure of fundamental value is observable; the bubble in closed-end country funds in the late 1980s is instructive here, as are the bubbles that occur in experimental asset markets. According to the efficient-market hypothesis, this doesn't happen, so any data is wrong. For closed-end country funds, observers can compare the stock prices to the net asset value per share. For experimental asset markets, observers can compare the stock prices to the expected returns from holding the stock. In both instances, closed-end country funds and experimental markets, stock prices diverge from fundamental values. Nobel laureate Dr. Vernon Smith has illustrated the closed-end country fund phenomenon with a chart showing prices and net asset values of the Spain Fund in 1989 and 1990 in his work on price bubbles.

At its peak, the Spain Fund traded near $35, nearly triple its Net Asset Value of about $12 per share. At the same time the Spain Fund and other closed-end country funds were trading at substantial premiums, the number of closed-end country funds available exploded thanks to many issuers creating new country funds and selling the IPOs at high premiums, it only took a few months for the premiums in closed-end country funds to fade back to the more typical discounts at which closed-end funds trade. Those who had bought them at premiums had run out of "greater fools". For a while, the supply of "greater fools" had been outstanding. A rising price on any share will attract the attention of investors. Not all of those investors are willing or interested in studying the intrinsics of the share and for such people the rising price itself is reason enough to invest. In turn, the additional investment will provide buoyancy to the price, thus completing a positive feedback loop. Like all dynamic systems, financial markets operate in an ever-changing equilibrium, which translates into price volatility.

However, a self-adjustment takes place normally: when prices rise more people are encouraged to sell, while fewer are e

George Brown Arfken is an American theoretical physicist and the author of several mathematical physics texts. He was a physics professor at Miami University from 1952 to 1983 and the chair of the Miami University physics department 1956–1972, he is an emeritus professor at Miami University. Arfken is an authority on Canadian philately. Arfken received a Bachelor of Engineering degree from Yale University in 1943, he earned a Master's degree both at Yale. Arfken married Carolyn Dines, a graduate of Westminster College of Pennsylvania, in 1949, they raised three children together, she died in 1997. In 1998, Arfken endowed a scholar-in-residence program in her name at Miami University. In retirement Arfken played a major role in developing the postal history of Canada for the 60-year period 1851–1911, following the pioneering work of Allan Steinhart; this was a study of the postal rates, the routes the mail followed, the postal markings on the envelopes and postcards. Arfken wrote one book on the United States' first postage-due stamps and with coauthors, nine books on the early Canadian postage and registration stamps.

In addition there were over 250 articles in philatelic journals. Articles1949: S-Wave Proton-Proton Scattering from 0.2 to 40 Mev for the Yukawa and Gauss Error Potentials, Physical Review Volume 75 1953: A Vector Addition Coefficient Identity, Physical Review Volume 92 1961: Ionization of the interplanetary gas, Los Alamos Scientific Lab 1973: Comment on “Elementary Use of Spheroidal Coordinates”, American Journal of Physics Volume 41, Issue 12, pp. 1375Books1966: Mathematical Methods for Physicists ISBN 0123846544 1989: University Physics ISBN 0155929747, coauthored with David F. Griffing and Donald C. Kelly 1989: Canada's Small Queen Era - Postage Usage During the Small Queen Era, 1870-1897 2003: Essential Mathematical Methods for Physicists ISBN 9780120598779, coauthored with Hans J. Weber, Frank E. Harris

This article refers the mainframe text editor. For the IEEE technical society, see Computer-Aided Design Technical Committee. CANDE is a command line shell and text editor on the MCP operating system which runs on the Unisys Clearpath series of mainframes. Implemented on Burroughs large systems, it has a range of features for interacting with the operating system execution environment, focused on executing and compiling programs, creating, moving and deleting files in general, its full name is CANDE MCS. MCS, or Message Control Subsystem is the general form of a systems program in the Burroughs architecture; as an MCS, CANDE is more than just an editor. The editing capabilities of CANDE are anachronistic for casual editing as they predate full screen and graphical editors. CANDE was used on the Burroughs CMS range, with similar syntax. CANDE provides a command-line interpreter and line editor, although unlike the modern interpretation of an operating system command line interpreter, the CANDE commands are compiled into the CANDE MCS, as shell like capabilities are provided by WFL.

Other notable features and functions include: Create and maintain data and program files Compile and execute programs Access and display information about the data communication network including terminal communication lines and remote devices Dynamically alter the communication network Access and display job and task information Utility functions In addition to these features CANDE has an on-line help facility. For extra speed, CANDE implemented user context switching by swapping a block at the top of the stack; this novel method broke several assumptions built into the design of Burroughs large systems, in particular the handling of virtual memory descriptors, meant that CANDE itself had to be written in DCALGOL with system-level privileges. Architecturally, CANDE is split into two main sections: a primary, single-instanced main process supporting up to 255 simultaneous users, one or more worker stacks; the main process is called BUMP. It receives all input messages, including input from users.

Simple requests which can be executed without delay and do not involve any I/O such as disk access are handled immediately. Other requests are handled by one of the worker processes; the worker process is called GRIND. Each GRIND process has by default five pseudo-threads which carry out the work; the internal threading model for context switching selects one of the worker pseudo-threads per GRIND process and makes it the executing context. This is achieved by copying it to the top of the stack; when the worker process needs to execute I/O or other asynchronous activity, it initiates the action, marks what it is waiting for, calls the context-switching function, which selects a different context for execution. CANDE operates by careful separation of data; each possible user connection is assigned an index into a main array called the station array, or STA. The current station index is named STAX. There are multiple words of state data per station, but they are stored with all of the first words together, followed by all of the second words, etc.

This allows CANDE to index into the array using only addition, not multiplication. CANDE was written in 1973 by Darrel F. High, it was taken over by Randall Gellens in 1984, at which point the library maintenance routines were rewritten to allow for expanded capabilities, a slew of utilities were added using the "?" syntax, several architectural improvements were made. It was transferred to the Santa Barbara plant, to India; the "?" syntax allowing for control during program execution, grew to include a number of utilities. Comparison of command shells Work Flow Language Burroughs B5500 Quick CANDE Reference Card for B5500 TSS 1042710 circa 1970 B6700, B7700 CANDE Reference card 5001050 July 1975 at bitsavers.org B7000, B6700 CANDE Reference card 5011349 October 1979 at bitsavers.org