Zeige, dass die R {\displaystyle {}\mathbb {R} } -Algebren R [ X , Y , Z ] / ( Z 2 − X 2 − Y 2 ) {\displaystyle {}\mathbb {R} [X,Y,Z]/(Z^{2}-X^{2}-Y^{2})} und R [ X , Y , Z ] / ( Z 2 − X Y ) {\displaystyle {}\mathbb {R} [X,Y,Z]/(Z^{2}-XY)} isomorph
![{\displaystyle {}\mathbb {R} [X,Y,Z]/(Z^{2}-X^{2}-Y^{2})}](../../../../../I/929572c4f805188258e157f89dbc373df8f16f10.svg)
![{\displaystyle {}\mathbb {R} [X,Y,Z]/(Z^{2}-XY)}](../../../../../I/672ca6f1cd6d7952bdaef9f17f92bdb753ea4c70.svg)
