# What information can be learned from the Eigenvalues?

**URL:** <https://forum.dynare.org/t/what-information-can-be-learned-from-the-eigenvalues/23229>\
**Category:** Dynare help (legacy posts)\
**Created:** [4 October 2023 10:02 UTC](https://forum.dynare.org/t/what-information-can-be-learned-from-the-eigenvalues/23229 "2023-10-04T10:02:42Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![LouisC](https://forum.dynare.org/letter_avatar_proxy/v4/letter/l/d6d6ee/32.png) [@LouisC](https://forum.dynare.org/u/LouisC)\
**Post date:** [4 October 2023 10:02 UTC](https://forum.dynare.org/t/what-information-can-be-learned-from-the-eigenvalues/23229/1 "2023-10-04T10:02:42Z")

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Dear all,

What information can you learn from the below eigenvalues as there are three values equal to 1 and one value is infinite?  
EIGENVALUES:  
Modulus Real Imaginary

```
   1.583e-16 1.583e-16 0
        0.02 -0.02 0
        0.16 0.16 0
      0.3383 0.3383 0
        0.64 0.64 0
      0.7464 0.7464 0
        0.76 0.76 0
        0.76 0.76 0
         0.8 0.8 0
        0.99 0.99 0
        0.99 0.99 0
           1 1 0
           1 1 0
           1 1 0
       1.118 1.075 0.304
       1.118 1.075 -0.304
       1.128 1.113 0.1842
       1.128 1.113 -0.1842
       1.932 1.782 0.7467
       1.932 1.782 -0.7467
           2 2 0
         Inf Inf 0

```

There are 8 eigenvalue(s) larger than 1 in modulus  
for 8 forward-looking variable(s)

The rank condition is verified.

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**Author:** ![jpfeifer](https://forum.dynare.org/user_avatar/forum.dynare.org/jpfeifer/32/5044_2.png) [@jpfeifer](https://forum.dynare.org/u/jpfeifer)\
**Post date:** [4 October 2023 13:15 UTC](https://forum.dynare.org/t/what-information-can-be-learned-from-the-eigenvalues/23229/2 "2023-10-04T13:15:18Z")

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The generalized eigenvalues are relevant for the Blanchard-Kahn conditions. The infinite one is not noteworthy. The unit roots are the ones to keep in mind. They will usually imply that shocks may have permanent effects.

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**Author:** ![LouisC](https://forum.dynare.org/letter_avatar_proxy/v4/letter/l/d6d6ee/32.png) [@LouisC](https://forum.dynare.org/u/LouisC)\
**Post date:** [4 October 2023 16:21 UTC](https://forum.dynare.org/t/what-information-can-be-learned-from-the-eigenvalues/23229/3 "2023-10-04T16:21:02Z")

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Thanks professor, does that mean there are three unit root process in the model?

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**Author:** ![jpfeifer](https://forum.dynare.org/user_avatar/forum.dynare.org/jpfeifer/32/5044_2.png) [@jpfeifer](https://forum.dynare.org/u/jpfeifer)\
**Post date:** [4 October 2023 18:17 UTC](https://forum.dynare.org/t/what-information-can-be-learned-from-the-eigenvalues/23229/4 "2023-10-04T18:17:48Z")

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It seems so.