Jul
2
awarded  Curious
Apr
24
comment Why do Integer Relation Algorithms (e.g. PSLQ) not solve the subset sum problem?
@pyramids: 1000 x+ 1001 y = 1 has inifintely many integer solutions but no 0,1 solutions. But even if an equation has a 0,1 solution, why do you expect that an algorithm for finding one of the infinitely many integer solutions should always produce the 01 solution eceot in rare cases??
Apr
24
comment Why do Integer Relation Algorithms (e.g. PSLQ) not solve the subset sum problem?
@pyramids: An algorithm for solving the integer constrained problem in polynomial time will just find some integer relation. This is very unlikely to be a (0,1) solution (which might not even exist). It cannot get stuck since it is not based on enumerating near solutions.
Apr
20
answered Why do Integer Relation Algorithms (e.g. PSLQ) not solve the subset sum problem?
Apr
19
answered Basis reduction and continued fractions
Apr
19
answered What is a good introduction to quantities such as the norm of a lattice and of short vectors in the context of lattice reduction?
Apr
19
asked Upper bound on the product of norms of vectors in a lattice basis
Mar
21
answered What are the properties of this Poisson algebra?
Mar
3
awarded  Yearling
Mar
3
awarded  Yearling
Dec
2
accepted classical solutions of PDE with mixed boundary conditions
Dec
2
comment classical solutions of PDE with mixed boundary conditions
Thanks. These and especially their reference to Azzam and Kreyszig are very useful!
Nov
13
comment Eigenvalues of a bipartite graph
@Shahab: It implies that $k|x|=A|x|$. For if this fails then there is strict inequality in at least one component, and multiplication by $u^T>0$ gives a strict inequality, contradiction.
Nov
9
comment Spectrum of a Block Matrix
@Timothy: intuitively: Draw a graph of the corresponding quadratic functions and you'll see where the inequalities hold. - formally: complete the squares, take square roots, and discard the signs not compatible with the case.
Nov
8
answered If $d^2|p^{11}$ where $p$ is a prime, explain why $p|\frac{p^{11}}{d^2}$.
Nov
8
answered Spectrum of a Block Matrix
Nov
7
comment Spectrum of a Block Matrix
What is your motivation for this conjecture?
Nov
7
answered Eigenvalues of a bipartite graph
Nov
6
comment Number of local maxima of a function
@EwanDelanoy: $F(x)=c$ is the quotient of two polynomials of degree $2k$. So my original $2k-1$ was one off. I corrected the mistake.
Nov
6
revised Number of local maxima of a function
corrected a mistake in the degree