tetragonalK3 -- tetragonal K3 surface

i1 : S = tetragonalK3 11

o1 = K3 surface with rank 2 lattice defined by the intersection matrix: | 20 4 |
                                                                        | 4  0 |
     -- (1,0): K3 surface of genus 11 and degree 20 containing elliptic curve of degree 4 (GM fourfold) 
     -- (1,1): K3 surface of genus 15 and degree 28 containing elliptic curve of degree 4 
     -- (1,2): K3 surface of genus 19 and degree 36 containing elliptic curve of degree 4 
     -- (1,3): K3 surface of genus 23 and degree 44 containing elliptic curve of degree 4 
     -- (1,4): K3 surface of genus 27 and degree 52 containing elliptic curve of degree 4 (GM fourfold) 
     -- (1,5): K3 surface of genus 31 and degree 60 containing elliptic curve of degree 4 
     -- (1,6): K3 surface of genus 35 and degree 68 containing elliptic curve of degree 4 (GM fourfold) 
     -- (1,7): K3 surface of genus 39 and degree 76 containing elliptic curve of degree 4 
     -- (2,0): K3 surface of genus 41 and degree 80 containing elliptic curve of degree 8 
     -- (1,8): K3 surface of genus 43 and degree 84 containing elliptic curve of degree 4 


o1 : Lattice-polarized K3 surface

i2 : S' = S(1,0);

o2 : Embedded K3 surface

i3 : map(S',0,1)

o3 = multi-rational map consisting of one single rational map
     source variety: K3 surface of genus 11 and degree 20 in PP^11
     target variety: PP^1

o3 : MultirationalMap (rational map from S' to PP^1)