There was the revolution in Tibet which we pretended did not exist.

There are two kinds of microsporogenesis: successive and simultaneous ( although intermediates exist ).

There is considerable speculation as to why the observable universe is apparently composed almost entirely of matter ( as opposed to a mixture of matter and antimatter ), whether there exist other places that are almost entirely composed of antimatter instead, and what sorts of technology might be possible if antimatter could be harnessed.

There exist pairs of long and short vowels with overlapping vowel quality giving Australian English phonemic length distinction, which is unusual amongst the various dialects of English, though not unknown elsewhere, such as in regional south-eastern dialects of the UK and eastern seaboard dialects in the US .< ref >

There is no scientifically accepted evidence that any such powers exist or that any anomalous operations have been observed in reality.

There is no clear consensus as to how many types of bipolar disorder exist.

There is general consensus that supermassive black holes exist in the centers of most galaxies.

There also exist today several federal constitutional monarchies.

There exist at least two different types of constitutional monarchies in the modern world-executive and ceremonial.

There also exist open-source applications written in Common Lisp, such as:

* There exist integers x and y such that ax + by = 1 ( see Bézout's identity ).

* There exist context-sensitive languages which are not context-free.

There exist programs that generate " human-sounding " melodies by using a vast database of phrases.

There exist many kinds of isomerism in coordination complexes, just as in many other compounds.

There exist laws restricting or regulating circumcision, some dating back to ancient times.

There exist, as yet, few comprehensive studies of the global division of labour ( an intellectual challenge for researchers ), although the ILO and national statistical offices can provide plenty of data on request for those who wish to try.

There does exist in Filipino an equivalent, gender-neutral term for the professional that carries the more general notion of " healer ", traditional ( for example, an albuláryo ) or otherwise: manggagámot.

There exist some very common erroneous ideas about the Inuit.

There also exist planetary-mass objects that orbit brown dwarfs and other bodies that " float free " in space not bound to any star ; however, the term " planet " is not always applied to these objects.

There exist two types of electric charges, called positive and negative.

There exist other formulations of rules, which are not in everyday language, understandable only to computer scientists.

There have been attempts to resolve the Fermi paradox by locating evidence of extraterrestrial civilizations, along with proposals that such life could exist without human knowledge.

There also exist a host of games where the term " graffiti " is used as a synonym for " drawing " ( such as Yahoo!

There may exist multiple cages for a given girth.

There is a large risk of landslides along the river and historical notes of 15 landslides exist.

There is, of course, nothing special about choosing the z-axis: according to quantum mechanics the spin singlet state may equally well be expressed as a superposition of spin states pointing in the x direction.

There must be some unknown mechanism acting on these variables to give rise to the observed effects of " non-commuting quantum observables ", i. e. the Heisenberg uncertainty principle.

* There are always vacuum fluctuations of the electromagnetic field, according to quantum mechanics.

There are two main categories of identical particles: bosons, which can share quantum states, and fermions, which do not share quantum states due to the Pauli exclusion principle.

There is another quantity of quantized angular momentum, called the orbital angular momentum ( quantum number L ), that comes in increments of 1 ħ, which represent the angular moment due to quarks orbiting around each other.

There is a classical analogue to the quantum no-cloning theorem, which we might state as follows: given only the result of one flip of a ( possibly biased ) coin, we cannot simulate a second, independent toss of the same coin.

There are a variety of interpretations of the constants ' values, including that of a divine creator ( the apparent fine-tuning is actual and intentional ), or that ours is one universe of many in a multiverse ( e. g. the Many-worlds interpretation of quantum mechanics ), or even that a universe without the capacity for conscious beings cannot exist.

There is speculation that the zeros of the zeta function are connected to the energy levels of complex quantum systems.

There are numerous mathematically equivalent formulations of quantum mechanics.

There are a number of technical challenges in building a large-scale quantum computer, and thus far quantum computers have yet to solve a problem faster than a classical computer.

There are a number of quantum computing models, distinguished by the basic elements in which the computation is decomposed.

There is a common misconception that quantum computers can solve NP-complete problems in polynomial time.

There is also a correspondence between confinement in QCD-the fact that the color-field is only different from zero in the interior of hadrons-and the behaviour of the usual magnetic field in the theory of type-II superconductors: there the magnetism is confined to the interiour of the Abrikosov flux-line lattice, i. e., the London penetration depth λ of that theory is analogous to the confinement radius R < sub > c </ sub > of quantum chromodynamics.

There is currently no complete quantum theory of the remaining fundamental force, gravity, but many of the proposed theories postulate the existence of a graviton particle that mediates it.

There are several theories using the QFT framework, such as quantum electrodynamics and quantum chromodynamics.

There are two common ways of developing a quantum field: the path integral formalism and canonical quantization.

There are several shortcomings to the above description of quantum mechanics which are addressed by quantum field theory.

There is a lack of experimental evidence relating to quantum gravity, and classical physics adequately describes the observed effects of gravity over a range of 50 orders of magnitude of mass, i. e., for masses of objects from about 10 < sup >− 23 </ sup > to 10 < sup > 30 </ sup > kg.

There are other points of tension between quantum mechanics and general relativity.

There are a number of proposed quantum gravity theories.