论文标题
Sorgenfrey线可数功率的D属性的反向感应证明
Reverse induction proof of D property of the countable power of the Sorgenfrey line
论文作者
论文摘要
我们提出了一种新的证明方法，我们称之为反向归纳。此方法允许建立产品的某些属性$ \ prod _ {{i} = 0}^{\ infty} {x} {x} _ {i} $，通过从$ \ prod _ {{i} = {n} = {n} +1} +1}+ifty}^{ $ \ prod _ {{i} = {n}}}^{\ infty} {x} _ {i} $对于任意天然$ {n} $。使用这种方法，我们回答了E. K. van Douwen和W. F. Pfeffer在1979年提出的一个问题，证明了Sorgenfrey线的可数功率是D空间。
We present a new method of proof, which we call reverse induction. This method allows to establish certain properties of a product $\prod_{{i}=0}^{\infty}{X}_{i}$ by making a kind of "reverse induction step" from $\prod_{{i}={n}+1}^{\infty}{X}_{i}$ to $\prod_{{i}={n}}^{\infty}{X}_{i}$ for an arbitrary natural ${n}$. Using this method we answer a question posed by E. K. van Douwen and W. F. Pfeffer in 1979 by proving that the countable power of the Sorgenfrey line is a D-space.
