#### top active problems

mathematics - 2017-03-19T17:26:44Z ago

Evolutionary theories
defined
A gene can be expressed at various stages of life. Therefore, natural selection can support lethal and harmful alleles, if their expression occurs after reproduction. Senescence may be the product of such selection.[25][26][27] In addition, ageing is believed to have evolved because of the... Read more

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mathematics - 2017-03-19T17:26:44Z ago

The problem of finding the ultimate core model
defined
The problem of finding the ultimate core model, one that contains all large cardinals.

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mathematics - 2017-03-19T17:26:44Z ago

prime quadruplets
divided
1 subproblem
Are there infinitely many prime quadruplets?

mathematics - 2017-03-19T17:26:44Z ago

Chvátals toughness conjecture
defined
that there is a number t such that every t-tough graph is Hamiltonian

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mathematics - 2017-03-19T17:26:44Z ago

Lyapunovs second method for stability
defined
For what classes of ODEs, describing dynamical systems, does the Lyapunov’s second method formulated in the classical and canonically generalized forms define the necessary and sufficient conditions for the (asymptotical) stability of motion?

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mathematics - 2017-03-19T17:26:44Z ago

Furstenberg conjecture
defined
Is every invariant and ergodic measure for the x2, x3 action on the circle either Lebesgue or atomic?

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mathematics - 2017-03-19T17:26:44Z ago

Pentagonal tiling
defined
15 types of convex pentagons are known to monohedrally tile the plane, and it is not known whether this list is complete

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mathematics - 2017-03-19T17:26:44Z ago

The einstein problem
defined
Is there a two-dimensional shape that forms the prototile for an aperiodic tiling, but not for any periodic tiling?

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chemistry - 2017-03-19T17:26:44Z ago

nature of strong gold-chalcogens in thiols
defined
What is the nature of strong gold-chalcogens in thiols and other organochalcogens (i.e., sulfur and higher chalcogen-containing organic compounds)?

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chemistry - 2017-03-19T17:26:44Z ago

alpha effect
defined
What is the origin of the alpha effect, that is, that nucleophiles with an electronegative atom with lone pairs adjacent to the nucleophilic center are particularly reactive?

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chemistry - 2017-03-19T17:26:44Z ago

chirality
defined
Is an abiologic origin of chirality as is found in (2R)-2,3-dihydroxypropanal (D-glyceraldehyde), and also in amino acids, sugars, etc., possible?

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organic chemistry - 2017-03-19T17:26:44Z ago

electromagnetic energy to chemical energy
defined
How can electromagnetic energy (photons) be efficiently converted to chemical energy? For instance, can water be efficiently split to hydrogen and oxygen using solar energy?[3][4]

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chemistry - 2017-03-19T17:26:44Z ago

Feynmanium
defined
Is Feynmanium the last chemical element that can physically exist? That is, what are the chemical consequences of having an element with an atomic number above 137, whose 1s electrons must travel faster than the speed of light?[1][2]

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chemistry - 2017-03-19T17:26:44Z ago

high temperature superconductors
defined
What are the electronic structures of high-temperature superconductors at various points on their phase diagrams?

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