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Oct
22
answered If both $P$ and $Q$ are true , how can I tell that $P$ implies $Q$?
Oct
17
comment How Many Theorems (Tautologies) Exist of 5, 6, 7, 8, and 9 Letters?
@Mariano: Re: not counting NNx or C(x)(tautology) - you might be able to syntactically ignore the latter (if you enumerate a system that includes enumerating tautologies, but eliminating double negation seems hard (just intractable to create the system of equations). Anyway, might as well include those because those are viable tautologies.
Oct
17
revised How Many Theorems (Tautologies) Exist of 5, 6, 7, 8, and 9 Letters?
brief extra explanation
Oct
17
comment How Many Theorems (Tautologies) Exist of 5, 6, 7, 8, and 9 Letters?
@Mariano: sorry, it was typed on an iPhone..somehow hard to think in a really tiny screen! I'll try to embellish my answer to help explain.
Oct
17
comment How Many Theorems (Tautologies) Exist of 5, 6, 7, 8, and 9 Letters?
@Mariano: oh duh... but easy to miss.
Oct
17
comment How Many Theorems (Tautologies) Exist of 5, 6, 7, 8, and 9 Letters?
Above you say you get 290 for 8 vars, but in the sequence at the bottom you give 198. Which is it?
Oct
17
comment How Many Theorems (Tautologies) Exist of 5, 6, 7, 8, and 9 Letters?
@Doug: I only considered 2 variables because, well, I mistakenly read too fast (you mentioned the number '2') and because it's crazy complicated with more anyway. So then I'll take Mariano's advice as the real justification. Anyway, you'd probably want to parameterize your exploration by number of variables anyway...oh yeah and also the set of operators ({AND, NOT}, {AND, OR, NOT}, {AND, OR, NOT, IMPLIES}, {NAND}, etc...)
Oct
17
comment How Many Theorems (Tautologies) Exist of 5, 6, 7, 8, and 9 Letters?
@Mariano: it's context-free but not regular, for any number of variables. Infix or prefix doesn't matter - see my answer.
Oct
17
revised How Many Theorems (Tautologies) Exist of 5, 6, 7, 8, and 9 Letters?
extra explanation
Oct
17
comment How Many Theorems (Tautologies) Exist of 5, 6, 7, 8, and 9 Letters?
@Doug: just stick with two variables, letters x and y, as a first thing to compute. What are all the ways of getting a particular Boolean function using C, N, p, and q, if all you're doing is adding one operator? You have to check how -any- Boolean function could be reached by the two operators (when only two vars allowed).
Oct
17
answered How Many Theorems (Tautologies) Exist of 5, 6, 7, 8, and 9 Letters?
Oct
17
comment How Many Theorems (Tautologies) Exist of 5, 6, 7, 8, and 9 Letters?
Generate and test? That is, write a program to generate all possible wffs, and then do a truth table on each one.
Oct
16
comment Least-effort way from A to B via X
What have you tried so far?
Oct
5
comment On the automated solution of Olympiad problems
I think you just identified the difficulty in automated theorem proving: all mathematical research is devoted to solving problems in a definitive manner. And this is ostensibly automatable, except research papers are difficult to formalize, and even informal everyday -word- problems are difficult to translate to symbolism, at least automatically.
Oct
5
comment On the automated solution of Olympiad problems
See Is it possible to solve any euclidean geometry problem by computer? ...it's Groebner basis completion that solves them.
Oct
2
revised Coordinates and distance in higher dimensional spherical and hyperbolic space
added explanation
Oct
2
asked Coordinates and distance in higher dimensional spherical and hyperbolic space
Sep
17
awarded  Yearling
Sep
1
comment Is there a name for this strange solution to a quadratic equation involving a square root?
"A white horse is not a horse"
Sep
1
comment Function for number patterns
@nzifnab: I've modified my (incorrect) answer. Since it is wildly incorrect, I think it should be deleted. But I can't delete it since you've accepted it as most helpful. I suggest either: 1) unaccepting my answer and accepting the other answer since it is correct (I favor this one) or 2) if you really want me to keep my answer around because it was helpful, please comment as to that effect (but still you should probably switch acceptance to the other correct answer).