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Questions about the properties of vector spaces and linear transformations, including linear systems in general.

5 votes

A signature inequality?

Example found randomly: EDIT: Make one with positive coefficients: $A=\pmatrix{1&2&3\cr2&5&6\cr3&6&10}$ and $B=\pmatrix{1&1&2\cr1&2&6\cr2&6&21}$. EDIT: Here's how, with Magma I get about a 25% proba …
Junkie's user avatar
  • 2,704
2 votes

A signature inequality?

I get about 0.1% random in 3 for 4x4. Here is a "patterned" one: [146 37 12 0] [ 37 10 3 0] [ 12 3 1 0] [ 0 0 0 1] [ 1 0 0 0] [ 0 4221 202 -857] [ 0 202 10 …
Junkie's user avatar
  • 2,704
0 votes

A signature inequality?

Overnight search (about 25 million random 5x5) found: [ 835 791 -119 -1 981] [ 791 755 -113 0 931] [-119 -113 17 0 -140] [ -1 0 0 1 2] [ 981 931 -140 2 1166] [ 5 7 …
Junkie's user avatar
  • 2,704
0 votes

A signature inequality?

Here is Magma code that will construct a 10x10 example, with one eigenvalue about +10 and nine of -1. Note that Magma has little numerical linear algebra, so I do it myself. As can be seen in the fina …
Junkie's user avatar
  • 2,704