Minimum required information about the available memory, is not put in requirements to be met by the server on which you want to install WordPress. The requirements listed on page is missing information that is desirable to have 64mb of memory on the server.

Not enough memory will be revealed to us through the occasional display of a blank page, from the server logs we know there has been an error:

Fatal error: Allowed memory size of …

Such information should be given to the requirements, particularly that the errors that are generated by a lack of memory may occur sporadically, and not everyone viewing the server logs regularly.