[This paper](https://hal.inria.fr/file/index/docid/241199/filename/ajp-jphystap_1907_6_202_0.pdf) by Hadamard is often cited as being the source of the definition of well-posed and ill-posed problems. 


However, it is in French so I cannot verify that claim. 


Is there an English translation? 



Is there an English translation of Hadamard's classic French paper on well-posed problems?
No, there is no "official" English translation, however, [Google translate](https://translate.google.com/?hl=en&tab=TT) should work just fine, here is the translation of the first paragraph, *without any corrections from my side*:



> 
> The general question that we propose to study is the determination of
>  the solutions of a linear equation to the derivatives partial ones of
>  the second order (this is the case to which we shall confine
>  ourselves) by data at the limits. In other words, we have to summarize
>  the results obtained in relation to the following two questions:  
> 
>  1) What are the data required to determine a solution of a partial
>  differential equation?  
> 
>  2) How can we calculate the solution
>  according to the data provided?  
> 
>  These two questions are precisely
>  those which Mr. Poincaré his important discourse *On the Reports of
>  Pure Analysis and Mathematical Physics* (International Congress of
>  Mathematicians, Zurich, 1897), cited as an example of the aid which
>  Physics is capable of bringing to analysis. And, indeed, there is
>  perhaps no case in which the conclusion which he has developed is more
>  strikingly apparent:  
> 
>  • It is mathematical physics that shows us what
>  problems we must ask ourselves.  
> 
>  • It is also what makes us foresee
>  the solution.
> 
> 
> 


(Incidentally, a nice description of how physics can help mathematics.)




---


Following a suggestion by Sylvain Jullien, I tried the translator at [DeepL.com](https://www.deepl.com/translator), on the same paragraph. Remarkably similar translation, actually, I presume they use pretty much the same neural network architecture as Google.



> 
> The general question that we propose to study is the determination of
>  the solutions of a linear equation to derivatives partial second order
>  data (this is the case to which we will confine ourselves) with data
>  at the limits. In other words, we have to summarize the results
>  achieved with respect to the following two-pronged question:  
> 
>  1) What is
>  the evidence to determine a solution to an partial derivatives?  
> 
>  2) How
>  to calculate the solution based on data so provided?  
> 
>  These two
>  questions are precisely those which Mr Poincaré, in his important
>  discourse *On the reports of Pure Analysis and Mathematical Physics*
>  (International Congress of Mathematicians, Zurich, 1897) cited as an
>  example of the help that Physics is likely to bring to Analysis. And,
>  indeed, there may not be any case in which the conclusion that he came
>  to is more striking:  
> 
>  • It is mathematical physics that shows us which
>  problems we must face.  
> 
>  • It is also what makes us foresee the solution.
> 
> 
> 




---


... and just for completeness, here is what [Microsoft Translator](https://www.bing.com/translator) produces (somewhat less to my liking):



> 
> The general question we propose to study is the determination of the
>  solutions of a linear equation to the derivatives partial second order
>  (this is the case we will confine ourselves to) by data to the limits.
>  In other words, we have to sum up the results gained relativity to the
>  following double question:  
> 
>  1) What are the data to determine a solution
>  of a equation to partial derivatives?  
> 
>  2) How can the solution be
>  calculated according to of the data so provided?  
> 
>  These two questions
>  are precisely those that Mr. Poincaré, in his important speech on the
>  *Reports of Analyse pure and Mathematical physics* (International
>  Congress of Mathematicians, Zurich, 1897), cited as an example of the
>  aid that physics is likely to bring to the analysis. And, indeed,
>  there may be no cases in which more strikingly appears the conclusion
>  that it has developed:  
> 
>  • It is the mathematical physics that shows us
>  which problems we have to ask ourselves.  
> 
>  • She also makes us anticipate
>  the solution.
> 
> 
> 


