# Syntax question

**URL:** https://community.freefem.org/t/syntax-question/4093
**Category:** General Discussion
**Created:** [October 6, 2025, 2:00pm UTC](https://community.freefem.org/t/syntax-question/4093 "2025-10-06T14:00:37Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![pnegron](https://avatars.discourse-cdn.com/v4/letter/p/74df32/32.png) [@pnegron](https://community.freefem.org/u/pnegron)
#### Post date: [October 6, 2025, 2:00pm UTC](https://community.freefem.org/t/syntax-question/4093/1 "2025-10-06T14:00:37Z")

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What is the difference between the following code (please note the use of brackets in the P1):

mesh Th=square(10,10);  
fespace Wh(Th,[P1]);

and

mesh Th=square(10,10);  
fespace Wh(Th,P1);

Thanks you!

P. Negron.

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### Author: ![fb77](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/fb77/32/3796_2.png) [@fb77](https://community.freefem.org/u/fb77)
#### Post date: [October 7, 2025, 9:06am UTC](https://community.freefem.org/t/syntax-question/4093/2 "2025-10-07T09:06:08Z")

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It makes no difference. The two ways are valid.

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### Author: ![pnegron](https://avatars.discourse-cdn.com/v4/letter/p/74df32/32.png) [@pnegron](https://community.freefem.org/u/pnegron)
#### Post date: [October 7, 2025, 2:58pm UTC](https://community.freefem.org/t/syntax-question/4093/3 "2025-10-07T14:58:06Z")

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Thank you very much for your answer. Actually my question is related to the example code for eigenvalues for the Laplacian on the unit square. In that code the instruction:

```auto
varf b ([u1], [u2]) = int2d(Th)(u1*u2); //no boundary condition

```

is uses the brackets to “eliminate” or not using boundary conditions. In this case the functions u1 and u2 are scalar functions. How do I “eliminate boundary conditions when I have vector functions, say:

```auto
varf b ([u1,u2], [v1,v2]) = int2d(Th)(u1*v1+u2*v2); //no boundary condition 

```

Thank you.

Pablo Negron.

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<div class="post-metadata">

### Author: ![fb77](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/fb77/32/3796_2.png) [@fb77](https://community.freefem.org/u/fb77)
#### Post date: [October 8, 2025, 1:43pm UTC](https://community.freefem.org/t/syntax-question/4093/4 "2025-10-08T13:43:03Z")

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The brackets have nothing to do with boundary conditions.  
The comment `//no boundary condition` just says that the author of the code did not put any Dirichlet boundary condition here, i.e. nothing of the form `+on(1,u1=val)`