Here is a list of all the current tags in the system, ordered by the number of problems with that tag. This is a work in progress - if you have suggestions of new tags to be added, or that certain tags should be added or removed from a problem, please let me know.

• number theory : 117 solved out of 419
• graph theory : 75 solved out of 208
• ramsey theory : 33 solved out of 86
• geometry : 25 solved out of 84
• additive combinatorics : 28 solved out of 73
• unit fractions : 20 solved out of 48
• primes : 7 solved out of 43
• chromatic number : 20 solved out of 43
• combinatorics : 20 solved out of 37
• distances : 7 solved out of 37
• analysis : 16 solved out of 33
• arithmetic progressions : 8 solved out of 23
• sidon sets : 4 solved out of 23
• additive basis : 6 solved out of 21
• factorials : 3 solved out of 20
• turan number : 5 solved out of 20
• irrationality : 1 solved out of 19
• hypergraphs : 6 solved out of 19
• divisors : 8 solved out of 18
• cycles : 6 solved out of 18
• set theory : 4 solved out of 18
• binomial coefficients : 2 solved out of 18
• covering systems : 5 solved out of 17
• polynomials : 8 solved out of 13
• complete sequences : 2 solved out of 8
• probability : 4 solved out of 8
• discrepancy : 3 solved out of 7
• iterated functions : 0 solved out of 7
• powers : 0 solved out of 4
• convex : 3 solved out of 3
• group theory : 0 solved out of 3
• squares : 1 solved out of 3
• primitive sets : 1 solved out of 3
• diophantine approximation : 1 solved out of 2

In total there are 859 problems in the database of which 271 have been solved.