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Apr
6 |
awarded | Yearling |
Apr
3 |
comment |
Is the two variable fragment of arithmetic, i.e., theory of ($\mathbb{N}, + ,\times$), decidable?
Sorry, I should have asked "Is every sentence equivalent to a boolean combination of 2-quantifier formulas in prenex form?" Also, It would be helpful if you said what you mean by "the two variable fragment of arithmetic". |
Apr
3 |
comment |
Is the two variable fragment of arithmetic, i.e., theory of ($\mathbb{N}, + ,\times$), decidable?
In "two-variable arithmetic" does every sentence have an equivalent prenex form consisting of an $x$-quantifier and a $y$-quantifier (in some order) followed by an open formula? |
Jan
21 |
awarded | Good Answer |
Dec
16 |
comment |
How Symmetric is Diophantine Approximation using Fractions with Square Denominators?
These can't be all of the best approximations, because they are all less than the Liouville number. |
Dec
14 |
comment |
A question regarding a fragment of Robinson Arithmetic
In your language you can say that every element is even or odd. This is true in the non-negative integers under addition but false for the set of polynomials with non-negative leading coefficients (under addition, with successor defined in the obvious way.) |
May
18 |
awarded | Nice Question |
Apr
6 |
awarded | Yearling |
Apr
3 |
revised |
divisible by all standard prime numbers
deleted 2 characters in body |
Apr
2 |
revised |
divisible by all standard prime numbers
added 16 characters in body |
Apr
2 |
revised |
divisible by all standard prime numbers
deleted 32 characters in body |
Apr
2 |
revised |
divisible by all standard prime numbers
added 32 characters in body |
Apr
2 |
answered | divisible by all standard prime numbers |
Jan
22 |
awarded | Enlightened |
Jan
22 |
awarded | Nice Answer |
Sep
10 |
awarded | Enlightened |
Aug
27 |
comment |
Algorithm for determining when polynomial iteration is bounded?
@Per: Thank you for the reference to the result on IFS undecidability. Alas, I don't see how to the IFS result here. However the second point, about the map $x\to x-1/x$ seems really interesting. Do you have a reference? |
Aug
26 |
asked | Algorithm for determining when polynomial iteration is bounded? |
Jul
2 |
awarded | Curious |
Jun
14 |
awarded | Enlightened |