# Math Help - T-open

1. ## T-open

Hi,

my book says that "... If we wish to emphasize the topology T, then we refer to U as T-open, ..."

Does this then mean that U fullfils the topology properties?

Thanks a lot in advanced.

Honey $\pi$

2. Originally Posted by HoneyPi
Hi,

my book says that "... If we wish to emphasize the topology T, then we refer to U as T-open, ..."

Does this then mean that U fullfils the topology properties?
It means that U is an open set in the topology T. It's the topology T that has to fulfil the topology properties. The set U just has to satisfy the condition of being one of the open sets in that topology.

3. Originally Posted by Opalg
It means that U is an open set in the topology T. It's the topology T that has to fulfil the topology properties. The set U just has to satisfy the condition of being one of the open sets in that topology.
Thanks for your prompt reply!

It was too good to be true ....

Honey $\pi$