It is the shape of the parabolic reflectors used in mirrors, antenna dishes, and the like ; and is also the shape of the surface of a rotating liquid, a principle used in liquid mirror telescopes and in making solid telescope mirrors ( see Rotating furnace ).

The principle of parabolic reflectors has been known since classical antiquity, when the mathematician Diocles described them in his book On Burning Mirrors and proved that they focus a parallel beam to a point.

The operating principle of a parabolic antenna is that a point source of radio waves at the focal point in front of a paraboloidal reflector of conductive material will be reflected into a collimated plane wave beam along the axis of the reflector.

In mathematics, the maximum principle is a property of solutions to certain partial differential equations, of the elliptic and parabolic types.

Working principle of a corner reflector

Working principle of a corner reflector

Reference to two other concepts -- nationalism and sovereignty -- may help to reveal the contours of the new principle.

I fled, however, not from what might have been the natural fear of being unable to disguise from you that the things about my bridegroom -- in the sense you meant the word `` things '' -- which you had been galvanizing yourself to tell me as a painful part of your maternal duty were things which I had already insisted upon finding out for myself ( despite, I may now say, the unspeakable awkwardness of making the discovery on principle, yes, on principle, and in cold blood ) because I was resolved, as a modern woman, not to be a mollycoddle waiting for Life but to seize Life by the throat.

Since by the principle of optimality the remaining stages use an optimal Af-stage policy with respect to Af, we may enter section Af of the table at this state Af and read off the optimal policy for stage Af and the resulting state Af.

And due to the double jeopardy principle, the state or prosecution may never appeal a jury or bench verdict of acquittal.

Buddha said " Love all, so that you may not wish to kill any " This is a positive way of stating the principle of Ahimsa.

The anthropic principle is often criticized for lacking falsifiability and therefore critics of the anthropic principle may point out that the anthropic principle is a non-scientific concept, even though the weak anthropic principle, " conditions that are observed in the universe must allow the observer to exist ", is " easy " to support in mathematics and philosophy, i. e. it is a tautology or truism

The rigidity of his geographical strategy may be gathered from the prescription that this principle is never to be departed from.

In principle and in academic use, an arbitrage is risk-free ; in common use, as in statistical arbitrage, it may refer to expected profit, though losses may occur, and in practice, there are always risks in arbitrage, some minor ( such as fluctuation of prices decreasing profit margins ), some major ( such as devaluation of a currency or derivative ).

The principle of Schwerpunkt enabled the attacker to win numerical superiority at the point of the main effort, which in turn gave the attacker tactical and operational superiority even though the attacker may be numerically and strategically inferior along the entire front.

Those who ignore the effects of long run trade deficits may be confusing David Ricardo's principle of comparative advantage with Adam Smith's principle of absolute advantage, specifically ignoring the latter.

The suppers are normally held on or near the poet's birthday, 25 January, sometimes also known as Robert Burns Day or Burns Night ( Burns Nicht ), although they may in principle be held at any time of the year.

As a third issue, philosophers who dispute the validity of the Turing test may feel that it is possible, at least in principle, for verbal report to be dissociated from consciousness entirely: a philosophical zombie may give detailed verbal reports of awareness in the absence of any genuine awareness.

The vast majority of laws are now subject to the ordinary legislative procedure, which works on the principle that consent from both the Council and Parliament are required before a law may be adopted.

Inspired by John Locke, the fundamental constitutional principle is that the individual can do anything but that which is forbidden by law, while the state may do nothing but that which is authorized by law.

An underlying principle is that the chain may be considered a rigid body once it has attained equilibrium.

may be inclined to assign to the nameless inventor of the principle of limited liability, as applied to trading corporations, a place of honour with Watt and Stephenson, and other pioneers of the Industrial Revolution.

This has led a number of environmentalists to support the use of the precautionary principle in policy making, which ultimately asserts that we don ’ t know how certain actions may affect the environment, and because there is reason to believe they may cause more harm than good we should refrain from such actions.

Given the conceptual context within which ancient thought thrived, how could anyone have questioned this principle??

It was indeed a remarkable feat that a man who had had no experience of bridge building should have applied the principle of the arch, which appears in his famous bridges at Portsmouth, Haverhill, and Philadelphia.

By applying this general principle, a great number of complex compounds of osmium, ruthenium, iridium, and rhenium, with triphenylphosphine, triphenylarsine, and triphenylstibine have been obtained in this laboratory during the past few years.

The central city areas, in other words, exhibit the two characteristics which violate the life principle of congregations of the major denominations: they have too few middle-class people ; ;

In any case, anyone who fails to make significant distinction between primary and secondary applications of economic pressure would in principle already have justified that use of economic boycott as a means which broke out a few years ago or was skillfully organized by White Citizens' Councils in the entire state of Mississippi against every local Philco dealer in that state, in protest against a Philco-sponsored program over a national TV network on which was presented a drama showing, it seemed, a `` high yellow gal '' smooching with a white man.

Such a decision should have placed a powerful weapon in the hands of the entire housing industry, but there is little evidence that realtors, or at least their associations, have repudiated the principle in such clauses.

Three elements have been important in holding the Communion together: First, the shared ecclesial structure of the component churches, manifested in an episcopal polity maintained through the apostolic succession of bishops and synodical government ; second, the principle of belief expressed in worship, investing importance in approved prayer books and their rubrics ; and third, the historical documents and standard divines that have influenced the ethos of the Communion.

Also, as we now know, bosons also have antiparticles, but since bosons do not obey the Pauli exclusion principle ( only fermions do ), hole theory does not work for them.

Samuel Clemens ( Mark Twain ) is also known to have spread the story while lecturing, personalizing it by adding " I have a higher and greater standard of principle.

All versions of the principle have been accused of discouraging the search for a deeper physical understanding of the universe.

These groupings have since been revised to improve consistency with the Darwinian principle of common descent.

Attempts have been made to connect both " Omanus " and " Haman " with the Zoroastrian term Vohu Mana ; however this denotes the principle of " Good Thoughts " and is not the name of a deity.

Scots common law differs in that the use of precedents is subject to the courts ' seeking to discover the principle that justifies a law rather than searching for an example as a precedent, and principles of natural justice and fairness have always played a role in Scots Law.

Steven Weinberg and a number of string theorists ( see string landscape ) have used this as evidence for the anthropic principle, which suggests that the cosmological constant is so small because life ( and thus physicists, to make observations ) cannot exist in a universe with a large cosmological constant, but many people find this an unsatisfying explanation.

According to some versions of functionalism, even non-human systems, such as other animal species, alien life forms, or advanced computers can, in principle, have mental states.

It is particularly acute for people who believe in the possibility of philosophical zombies, that is, people who think it is possible in principle to have an entity that is physically indistinguishable from a human being and behaves like a human being in every way but nevertheless lacks consciousness.

: The claim that EPR effects violate the principle that information cannot travel faster than the speed of light have been countered by noting that they cannot be used for signaling because neither observer can control, or predetermine, what he observes, and therefore cannot manipulate what the other observer measures.

The Vedic literature, Srimad-Bhagavatam, reject from its very beginning kaitava-dharma or false philosophy, thus it frankly speaks about the principle of material life, and it does have a meaningful relation to celibacy.

These variations have been classified on the basis of the quasi-equivalence principle proposed by Caspar and Klug.

David Hume and later Paul Edwards have invoked a similar principle in their criticisms of the cosmological argument.