<p>Well, if you are talking about this</p>
<p><a href="https://en.wikipedia.org/wiki/Ramsey%E2%80%93Cass%E2%80%93Koopmans_model" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Ramsey%E2%80%93Cass%E2%80%93Koopmans_model</a></p>
<p>It is definitely a growth model (assuming consumption is less than output).</p>

CC BY-SA 4.0
2020-10-22T14:44:34.670Z
2020-10-22T14:44:34.670Z
Daniel
<p>No it is not. The benchmark Ramsey model allows for positive and negative investment. Treating the case of non-negative (or &quot;irreversible&quot; investment) is considered an extension.<br />
See Barro &amp; Sala-i-Martin (2004). Economic growth (2nd ed)</p>
<ul>
<li>Appendix 2B for a short discussion and</li>
<li>Section 5.1.2 pp 242-247 for an Endogenous growth model with irreversible investment and Human capital.</li>
</ul>
<p>For a more deep treatment, see<br />
Arrow and Kurz(1970).  Optimal Growth with Irreversible Investment in a Ramsey Model, Econometrica, Vol. 38(2), 331-344 .</p>

CC BY-SA 4.0
2020-10-22T17:30:58.980Z
2020-10-22T17:30:58.980Z
Alecos Papadopoulos
<p>I have a very fundamental question. I am currently searching for an economic growth model with non negative investment. Can someone tell me if the Ramsey model is one with non negative investment and if so - why? Thank you very much</p>

CC BY-SA 4.0
2020-10-19T18:54:00.073Z
what exactly do you mean by non-negative investment? In most growth models there will be some positive level of investment.
1muflon1
<ramsey>
Is the Ramsey model one with non negative investment?
Jan Kreischer
# Is the Ramsey model one with non negative investment?

(Asked by: username_0 on 2020-10-19)

I have a very fundamental question. I am currently searching for an economic growth model with non negative investment. Can someone tell me if the Ramsey model is one with non negative investment and if so - why? Thank you very much

**Tags:** ramsey
> **Comments:**
> **username_1**: what exactly do you mean by non-negative investment? In most growth models there will be some positive level of investment.  

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## 2 answers

### Answer by username_3 on 2020-10-22. Score: 3 | Accepted answer

No it is not. The benchmark Ramsey model allows for positive and negative investment. Treating the case of non-negative (or "irreversible" investment) is considered an extension.  
See Barro & Sala-i-Martin (2004). Economic growth (2nd ed)

* Appendix 2B for a short discussion and
* Section 5.1.2 pp 242-247 for an Endogenous growth model with irreversible investment and Human capital.

For a more deep treatment, see  
Arrow and Kurz(1970). Optimal Growth with Irreversible Investment in a Ramsey Model, Econometrica, Vol. 38(2), 331-344 .


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### Answer by username_2 on 2020-10-22. Score: 0

Well, if you are talking about this

<https://en.wikipedia.org/wiki/Ramsey%E2%80%93Cass%E2%80%93Koopmans_model>

It is definitely a growth model (assuming consumption is less than output).


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