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Let $X$ be the quotient space of the disk, $\{(x,y)\in \mathbb R^{2} \ | \ x^{2}+y^{2}\leq 1 \}$, obtained by identifying points on the boundary that are $120$ degrees apart. How can we find the fundamental group of $X$ ?

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    @hebele - if you have done the projective plane before (identify antipodal points - i.e. 180 degrees), you should able to do this! (and you should be able to guess the answer straight away)2011-06-03

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