Hello! I'm new here. I've been seeing this forum for a long time, but i never registered. I'd like to begin to contribute to this forum, i'll try it (even if my english doesn't help me).(adsbygoogle = window.adsbygoogle || []).push({});

So now, i ask you for help: i've to find an isometric immersion of the flat torus on [itex]\mathbb{R}^4[/itex]. I know that the function [itex]f:\mathbb{S}^1\times\mathbb{S}^1\rightarrow \mathbb{R}^4[/itex] given by [itex]f(\theta,\phi)=(\cos\theta,\sin\theta,\cos\phi, \sin \phi )[/itex] is the indicated function, but i don't know how to demonstrate that it's differential is inyective.

Thanks for your help!

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# Isometric Immersion of the Torus

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