# All Questions

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### Sketch a figure which has a group of symmetries of order 5.

I am trying to draw a shape which has only 5 symmetries I know Square has 8 Rectangle/parallelogram has 4 Triangle has 6 Circle has infinite how do i know which shape has only 5 I know that ...
6 views

### Infinite sets having no RE subsets

I'm back trying to learn recursion theory on my own. I'd like to prove the following result: There exists an infinite set having no infinite R.E. subset. Constructive comments are appreciated. Proof: ...
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### Efficient way of checking linear independence

Suppose I have a $4 \times 4$ matrix $A$ whose columns represent vectors $v_1,v_2,v_3,v_4$ in $\mathbb{R}^4$. Now, given that $\det{A} = 0$ (i.e. the vectors are linearly dependent), I want to make ...