The question is to show that a circle and a elipse are homomorphic in $R^{2}$.
I have two questions 1) should I consider only the boundary points of circles and elipse?
2) what is the suitable function for this?.
The question is to show that a circle and a elipse are homomorphic in $R^{2}$.
I have two questions 1) should I consider only the boundary points of circles and elipse?
2) what is the suitable function for this?.
Usually, yes, we mean only the contour by a 'circle' or 'ellipse'. For the solid circle, we rather use 'disk'. But here it doesn't matter.
In a suitable coordinate system, it's $(x,y)\mapsto (ax, by)$ for some $a,b>0$.