Some years ago one of us ( Novikov < sup > 10 </ sup >) briefly considered the possibility that CTCs might exist and argued that they cannot entail this type of causality violation: Events on a CTC are already guaranteed to be self-consistent, Novikov argued ; they influence each other around a closed curve in a self-adjusted, cyclical, self-consistent way.

However, some philosophers and scientists believe that time travel into the past need not be logically impossible provided that there is no possibility of changing the past, as suggested, for example, by the Novikov self-consistency principle.

If CTCs exist, their existence would seem to imply at least the theoretical possibility of time travel backwards in time, raising the spectre of the grandfather paradox, although the Novikov self-consistency principle seems to show that such paradoxes could be avoided.

This has been obtained by Novikov, Shifman, Vainshtein and Zakharov and can be written as

* 1901 – Pyotr Novikov, Russian mathematician ( d. 1975 )

Pyotr Sergeyevich Novikov (; 15 August 1901, Moscow, Russian Empire – 9 January 1975, Moscow, Soviet Union ) was a Soviet mathematician.

A quarter century later a 1975 paper by E. A. Novikov and a 1979 paper by H. Aref on chaotic advection finally brought this important earlier work to light.

This could mean that the Novikov self-consistency principle does not actually place any constraints on systems outside of the region of spacetime where time travel is possible, only inside it.

It was only in 1992 that Sergei Vasilievich Ivanov was able to prove an analogue of Novikov – Adian theorem: for any m > 1 and an even n ≥ 2 < sup > 48 </ sup >, n divisible by 2 < sup > 9 </ sup >, the group B ( m, n ) is infinite.

Another resolution, of which the Novikov self-consistency principle can be taken as an example, holds that if one were to travel back in time, the laws of nature ( or other intervening cause ) would simply forbid the traveler from doing anything that could later result in their time travel not occurring.

In 1990, commenting on the Novikov self-consistency principle ( in relation to sending objects or people through a traversable wormhole into the past, and the time paradoxes that could result ), Polchinski raised a potentially paradoxical situation involving a billiard ball sent through a wormhole which sends it back in time.

An alternative is to conjecture that, while time travel is possible, it never leads to paradoxes ; this is the Novikov self-consistency principle.

The Novikov self-consistency principle, also known as the Novikov self-consistency conjecture, is a principle developed by Russian physicist Igor Dmitriyevich Novikov in the mid-1980s to solve the problem of paradoxes in time travel, which is theoretically permitted in certain solutions of general relativity ( solutions containing what are known as closed timelike curves ).

The Novikov Principle is able to circumvent most commonly-cited temporal paradoxes which are often alleged to exist should time travel be possible ( and are often claimed to make it impossible ).

The Novikov self-consistency principle states that a time traveller would not be able to do so.

The Novikov Principle does not allow a time traveller to change the past in any way at all, but it does allow them to affect past events in a way that produces no inconsistencies — for example, a time traveller could rescue people from a disaster, and replace them with realistic corpses if history recorded that bodies of victims had been found.

The Novikov consistency principle assumes certain conditions about what sort of time travel is possible.

However, the Novikov self-consistency principle is intended to go beyond just the statement that history must be consistent, making the additional nontrivial assumption that the universe obeys the same local laws of physics in situations involving time travel that it does in regions of spacetime that lack closed timelike curves.

However, the series does not consistently obey the Novikov principle in episodes featuring time travel, as episodes like Time Squared and Yesterday's Enterprise show history being changed as a result of time travel.

* From wormhole to time machine: Comments on Hawking's Chronology Protection Conjecture, which also addresses the Novikov self-consistency principle

The Novikov self-consistency principle and Kip S. Thorne expresses one view on how backwards time travel could be possible without a danger of paradoxes.

Novikov formulated the Novikov self-consistency principle in the mid-1980s, an important contribution to the theory of time travel.

The Novikov self-consistency principle was anticipated by the tacit understanding of the Time Tunnel scientists that recorded history could not be altered although in episode four (" The Day The Sky Fell In ") the time travelers make it their concern to see to it that young Tony Newman escapes being killed in the Pearl Harbor bombing in order to prevent the adult Tony from ceasing to exist.

: Clearly Novikov did not see this brilliant tactical shot as he used up most of his time trying to come up with a good move.

Stated simply, the Novikov consistency principle asserts that if an event exists that would give rise to a paradox, or to any " change " to the past whatsoever, then the probability of that event is zero.

Other proposals which allow for backwards time travel but prevent time paradoxes, such as the Novikov self-consistency principle which would ensure the timeline stays consistent, or the idea that a time traveler is taken to a parallel universe while his original timeline remains intact, do not qualify as " chronology protection ".

With Igor Novikov and Don Page he developed the general relativistic theory of thin accretion disks around black holes, and using this theory he deduced that with a doubling of its mass by such accretion a black hole will be spun up to 0. 998 of the maximum spin allowed by general relativity, but never any farther ; this is probably the maximum black-hole spin allowed in Nature.

The quantum cohomology group of symplectic manifold M can be defined as the tensor products of the ordinary cohomology with Novikov ring Λ, i. e.

* Nikolay Novikov ( 1744 – 1818 ) Russian.

It was shown by Pyotr Novikov in 1955 that there exists a finitely generated ( in fact, a finitely presented ) group G such that the word problem for G is undecidable.

Time loop logic, coined by the roboticist and futurist Hans Moravec, is the name of a hypothetical system of computation that exploits the Novikov self-consistency principle to compute answers much faster than possible with the standard model of computational complexity using Turing machines.

Claims, arguments, or philosophical principles logically equivalent to the Novikov self-consistency principle have been published before Novikov's own publication.

* Novikov is alluded to by name in the comic Nth Man: The Ultimate Ninja.

* 1964-A. G. Doroshkevich and Igor Dmitrievich Novikov write an unnoticed paper suggesting microwave searches for the black-body radiation predicted by Gamow, Alpher, and Herman.

Igor Dmitriyevich Novikov () ( born November 10, 1935 in Moscow ) is a Russian ( and former Soviet ) theoretical astrophysicist and cosmologist.

They discussed this possibility.

Using the once popular vortex theory of gravity, the possibility of matter with negative gravity was discussed by William Hicks in the 1880s.

He hypothesized antiatoms, as well as whole antimatter solar systems, and discussed the possibility of matter and antimatter annihilating each other.

A proposed rail link between Ouagadougou and Pô in Burkina Faso and Kumasi and Boankra in Ghana, has been discussed with Ghanaian officials, and feasibility studies are being undertaken to explore this possibility, which would provide rail access to the inland port of Bonakra.

However, the possibility of actually constructing a conscious machine was probably first discussed by Ada Lovelace, in a set of notes written in 1842 about the Analytical Engine invented by Charles Babbage, a precursor ( never built ) to modern electronic computers.

Several delegates discussed the possibility of either removing or reducing Stalin's powers.

Information asymmetries and incomplete markets may result in economic inefficiency but also a possibility of improving efficiency through market, legal, and regulatory remedies, as discussed above.

R. T. Gould suggested something like a long-necked newt and Roy Mackal discussed this possibility, giving it the highest score ( 88 %) in his list of possible candidates.

The possibility that microorganisms exist was discussed for many centuries before their actual discovery in the 17th century.

At the same time, throughout early 1939, Germany and the Soviet Union had discussed a possibility of an economic deal involving industrial equipment and armament for the USSR in exchange for raw materials needed for German war production.

The possibility of aquatic locomotion via swimming has been discussed briefly in several papers ( Bennett 2001, 1994, and Bramwell & Whitfield 1974 ), and has been studied in detail at Michigan State University through the use of morphometrics and an extant phylogenetic bracket ( a morphologically comparative technique invented by Larry Witmer ).

" Sukeforth noticed that Clemente was being used as a bench player for the team and discussed the possibility of drafting Clemente to the Pirates with the team's manager, Max Macon.

In his The Limit of Accomplishment concerning Knowledge of the Heavens, he also discussed the possibility of heliocentrism.

After the surprising opening of 1970 toward conservatives, and the still discussed proposal of the Historic Compromise, he published a correspondence with Monsignor Luigi Bettazzi, the Bishop of Ivrea ; it was an astonishing event, since Pope Pius XII had excommunicated the Communists soon after World War II, and the possibility of any relationship between communists and Catholics seemed very unlikely.

The naval staff hoped to gain a success to influence postwar budget debates ... Since Raeder had already discussed with Hitler on 20 May the possibility of invading Britain, such a waste of German naval strength off the North Cape counts as one of the most egregious naval misjudgements of the war.

The idea for the Gremlin began in 1966 when design chief at American Motors, Richard A. Teague, and stylist Bob Nixon discussed the possibility of a shortened version of AMC's compact car and design sketches were prepared by Nixon.

He reports that he considered the possibility of life existing on other planets as an 8-year-old, but never discussed the idea with his family or teachers due to the prevalent religious ideology.

In the first film, Morticia and Gomez discussed how Mother and Father Addams were killed by an angry mob, removing any possibility that Grandmama could be Gomez's and Fester's mother.

Lucretia Mott met with Elizabeth Cady Stanton in Boston in 1842, and discussed again the possibility of a woman's rights convention.

His high-school football coach knew the football coach for Arizona State Frank Kush, and they discussed the possibility of him playing both sports.

During reunification, the two states discussed the possibility of drafting a new common constitution followed by a plebiscite, as envisioned in Art.

Although Adolf Hitler discussed with Ferdinand Porsche the possibility of military application of the Volkswagen as early as April 1934, it was not until January 1938, that high-ranking Third Reich army officials formally approached Porsche about designing an inexpensive, light-weight military transport vehicle that could be operated reliably both on-and off-road in even the most extreme conditions, suggesting that the Beetle could provide the basis for such a vehicle.

); the possibility of her being a daughter of Cisseus is also discussed.

They discussed the possibility of joining together in a federation to enhance co-operation amongst individual YMCA societies.