Hypothesis of efficient markets in finance, the assumption of market efficiency states that the price of assets traded in financial markets reflect all information known to the members of the market and all investors’ beliefs about the future. This hypothesis implies that it is possible to consistently achieve results exceed market except through luck or inside information. It also suggests that the future flow of news that will determine the stock price is random and can not be known in advance. The hypothesis of market efficiency is a central piece of the theory of efficient markets. It is a common mistake to believe that the efficiency hypothesis implies that investors behave rationally. The hypothesis allows some investors overreacts to news and other underreaction. The only thing required is that the reactions of investors are sufficiently random so it is not possible to obtain a benefit that exceeds the market.It is possible therefore that the market behaves irrationally for a long period of time. Crash, bubbles and depressions are always compatible with the hypothesis that such behavior is not predictable. The hypothesis is presented in three ways (weak form, semi-strong form and strong form). Each form has different implications for the functioning of the markets.
With the latter could disprove to who in respect of travel to the past, speak of the paradox of who kills his own grandfather when he was still a boy and that as a consequence of that Act could not have existed in the future to the not being able to be born. However this paradox does not exist in reality, because traveling to the past automatically change universe. I.e. it is not necessary to kill none of our ancestors. To be each one of us a source of energy that radiates its influence through our thoughts towards the entire universe in general and towards the people that surround us in particular (call them those who inhabit the planet Earth to exemplify) action that we print to our thoughts in America will directly influence the development of those living in Asia, because all beings who inhabit the universe are essentially one only partitioning for millions of people, but connected mentally. With the above I mean in the hypothetical case that within 1,000 years the man invented a spaceship that could travel at the speed of light and decided to move to the passed, would not need to landfall, with the only echo enter Earth’s atmosphere still remaining by an only second, such an act would influence to change the fate of all mankind.
Because that only second would have been sufficient to introduce the influence of the power of his thoughts in this universe of the past, which did not have their presence until then. With this I repeat what others have already said: one could travel to the future and return it without that modify its present, but instead could never return to the same present if you travel to the past, by what you’ve already specified. And here to introduce another hypothesis: the destination is not one only, they are infinite. As many as parallel universes exist.