Question about the relation between the Weierstrass equation and weighted projective space

283 Views Asked by At

I am reading a review on Toric Geometry for string theorists by Harald Skarke (arXiv:hep-th/9806059). In section 3, the author says

A standard way of describing an elliptic curve is by embedding it into $\mathbb{P}^2 = (\mathbb{C}^3\setminus\{0\})/(\mathbb{C}\setminus\{0\})$.....The elliptic curve is embedded in this space via the Weierstrass equation $$ \label{eq:w1}y^2 z = x^3 + a x z^2 + b z^3$$

An alternative description can be given in terms of the weighted projective space $\mathbb{P}^{(2,3,1)}$ defined just like $\mathbb{P}^2$, but with the equivalence relation changed to

$$(x, y, z) \sim (\lambda^2 x, \lambda^3 y, \lambda z) \quad \text{ for any } \lambda \in \mathbb{C}\setminus\{0\}$$

and the Weierstrass equation changed to

$$\label{eq:w2}y^2 = x^3 + a x z^4 + b z^6$$

Questions

  1. Given the description of the two projective spaces as embeddings in $\mathbb{C}^3$, how does one obtain the two Weierstrass equations?

  2. Is there a way to transform the first Weierstrass equation into the other?

Thanks in advance!