

A100200


Decimal Goedelization of antitheorems from propositional calculus, in Richard Schroeppel's metatheory of A101273.


5



151, 252, 1431, 1831, 2432, 2832, 3141, 3181, 3242, 3282, 11511, 12512, 14151, 15141, 15331, 15910, 21521, 22522, 24252, 25242, 25332, 25920, 31531, 32532, 33151, 33252, 91051, 91510, 92052, 92520, 114311, 118311, 124312, 128312, 141431, 141831, 142431
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OFFSET

1,1


COMMENTS

Blocks of 1's and 2s are variables: A = 1, B = 2, C = 11, D = 12, E = 21, ... Not (also written ) = 3; And = 4; Xor = 5; Or = 6; Implies = 7; Equiv = 8; Left Parenthesis = 9; Right Parenthesis = 0. Operator binding strength is in numerical order, Not > And > ... > Equiv. The nonassociative "Implies" is evaluated from Left to Right; A>B>C = is interpreted (A>B)>C. Redundant parentheses are permitted, so long as they are balanced and centered on a valid variable or sentential formula and not on the null character.
Besides A101273, there can also be the subsequence of theorems that can be proved within the more restricted Intuitionist logic; the sequence of wellformed formulas whose truth value is contingent on the truth values of their variables; and many others. As with A101273, I conjecture that a power law approximates the number of integers in this sequence, where the number with N digits is approximately N to the power of some real number D.
Comment from Ed Brims (ejbrims(AT)hotmail.com), Aug 18 2008: Quite interestingly, this sequence is quoted (in its original incorrect form) in the novel "The End of Mr Y" by Scarlett Thomas, towards the end of Chapter 12.


REFERENCES

Goedel, K. On Formally Undecidable Propositions of Principia Mathematica and Related Systems. New York: Dover, 1992.
Hofstadter, D. R. Goedel, Escher, Bach: An Eternal Golden Braid. New York: Vintage Books, p. 17, 1989.
Kleene, S. C. Introduction to Metamathematics. Princeton, NJ: Van Nostrand, p. 39, 1964.
Scarlett Thomas, "The End of Mr Y", Harcourt Books.


LINKS

Charles R Greathouse IV, Table of n, a(n) for n=1..10000
Eric Weisstein's World of Mathematics, Propositional Calculus
Eric Weisstein's World of Mathematics, Connective. See this for table of functions (and their notations) which corresponds to English conjunctions such as "and," "or," "not," etc. that takes one or more truth values as input and returns a single truth value as output. This includes ones used in A101273.
Eric Weisstein et al., Goedel Number.


FORMULA

Wellformed formulas that are always false (i.e. negations of theorems) represented as decimal integers in Richard Schroeppel's metatheory of A101273.


EXAMPLE

1431 corresponds to the sentence which violates the Law of the Excluded Middle: A ^ A.
33252 corresponds to the sentence, with square brackets being implicit parentheses, [ B ] xor B.
118311 corresponds to this sentence asserting the equivalence of the 3rd variable with its negation, C = C.


CROSSREFS

Cf. A101273, A101248.
Sequence in context: A059858 A152310 A070182 * A142575 A142657 A142760
Adjacent sequences: A100197 A100198 A100199 * A100201 A100202 A100203


KEYWORD

nonn,base


AUTHOR

Jonathan Vos Post, Dec 27 2004


EXTENSIONS

Sequence and example corrected by Charles R Greathouse IV, Oct 06 2009
Entries replaced by values from bfile.  N. J. A. Sloane, Oct 04 2010


STATUS

approved



