Plane quartics containing the ten vertices of a complete pentalateral and limits of them are called Lüroth quartics.The locus of singular Lüroth quartics has two irreducible components,both of codimension tw...Plane quartics containing the ten vertices of a complete pentalateral and limits of them are called Lüroth quartics.The locus of singular Lüroth quartics has two irreducible components,both of codimension two in P14.We compute the degree of them and discuss the consequences of this computation on the explicit form of the Lüroth invariant.One important tool is the Cremona hexahedral equations of the cubic surface.We also compute the class in M 3 of the closure of the locus of nonsingular Lüroth quartics.展开更多
《六顶思考帽》、《六双行动鞋》与《横向思维》并称为爱德华·狄波诺（Edward de Bono）创新思维三部曲。这位创新思维教学领域里的权威用《六顶思考帽》改变了人们的思考方式之后，《六双行动鞋》又使人们的行为方式产生重大变革...《六顶思考帽》、《六双行动鞋》与《横向思维》并称为爱德华·狄波诺（Edward de Bono）创新思维三部曲。这位创新思维教学领域里的权威用《六顶思考帽》改变了人们的思考方式之后，《六双行动鞋》又使人们的行为方式产生重大变革。在思考（帽子）＋行动（鞋子）=决策这个著名的方程式中，帽子代表思考，鞋子意味行动，由帽子作出的计划，交由鞋子来执行。不同样式与颜色的鞋子代表不同的行动方式，而行动方式则需依照具体情况而定。有意向再加上自己的行动，你最终就比别人走得快。展开更多
文摘Plane quartics containing the ten vertices of a complete pentalateral and limits of them are called Lüroth quartics.The locus of singular Lüroth quartics has two irreducible components,both of codimension two in P14.We compute the degree of them and discuss the consequences of this computation on the explicit form of the Lüroth invariant.One important tool is the Cremona hexahedral equations of the cubic surface.We also compute the class in M 3 of the closure of the locus of nonsingular Lüroth quartics.
文摘《六顶思考帽》、《六双行动鞋》与《横向思维》并称为爱德华·狄波诺（Edward de Bono）创新思维三部曲。这位创新思维教学领域里的权威用《六顶思考帽》改变了人们的思考方式之后，《六双行动鞋》又使人们的行为方式产生重大变革。在思考（帽子）＋行动（鞋子）=决策这个著名的方程式中，帽子代表思考，鞋子意味行动，由帽子作出的计划，交由鞋子来执行。不同样式与颜色的鞋子代表不同的行动方式，而行动方式则需依照具体情况而定。有意向再加上自己的行动，你最终就比别人走得快。
