?? polynomials in x,y, constant on y-axis .... ??? .... ?? "term with y must also contain x" ??? ....

1

x

xy

xyy

xyyy

?? not finitely generated ??? .... ??? bizarre that / if i never noticed this before ?? ... ???? ....

k[a,b] -> k[x,y]

a |-> x

b |-> xy

?? a=x, b=xy, c=xyy

ac=bb .... ???? ....

?? cones approaching allegedly "too big" one ... ??? ...

?? cocones approaching allegedly "too small" .... ???? ... ??? ....

?? some confusion / mix-up ?? ... ??? not giving blow-down i thought i wanted ... ??? .... ??? .... ?? vague idea was ... ?? having just noticed that blow-down seems to be a sort of ideal limit, and having been in search of an ideal limit recently, wondering whether this might be it ... ??? .... ??? ....

?? "localize at ideal" vs "blow-up ideal" .... ????? ..... ?? vs blow-down too .... ??? ....