Category:Open problems

• Lists of unsolved problems (16 P)
• Year of death unknown (1 C, 9,084 P)

B

• Bridge disasters of unknown cause (4 P)

C

• Undeciphered historical codes and ciphers (1 C, 20 P)
• Unsolved crimes (7 C, 7 P)

D

• Date of birth unknown (2,169 P)
• Date of death unknown (1,326 P)
• Unsolved deaths (26 C, 94 P)
• Unexplained disappearances (8 C, 22 P)

E

• Economic puzzles (19 P)

H

• Hypotheses (14 C, 98 P)

I

• Inscriptions of disputed origin (2 C, 22 P)

L

• Unsolved problems in linguistics (6 C, 10 P)
• Lost inventions (1 C, 16 P)
• Lost objects (6 C, 19 P)
• Lost places (5 C, 5 P)

P

• Unidentified people (11 C, 98 P)
• Philosophical problems (5 C, 44 P)
• Place of birth unknown (859 P)
• Place of death unknown (492 P)

S

• Scientific problems (8 C, 4 P)
• Year of song unknown (771 P)

T

• Unknown-strength tropical cyclones (4 P)

U

• U-boats sunk by unknown causes (31 P)
• Unexplained phenomena (8 C, 34 P)
• Unsolved problems in mathematics (6 C, 75 P)

W

• Works of unknown authorship (10 C, 253 P)

Y

• Year of birth unknown (1 C, 25,829 P)
• Year of establishment unknown (1 C, 39 P)
• Year of introduction unknown (6 P)

• Open problem

*

• Lists of unsolved problems

A

• Almáttki áss
• Alpha effect

B

• Binding problem

C

• Certificate revocation
• Controversies in autism

G

• Great Filter

H

• Hard problem of consciousness

O

• Overlapping markup

P

• Philosophy of artificial intelligence
• Potential applications of carbon nanotubes
• Problem of mental causation
• Publius Enigma

Q

• Quantum computing
• Glossary of quantum computing

S

• Space colonization

T

• Terraforming

V

• Vertiginous question