I have some questions regarding emptiness problem of turing machines when we have TM whivh accepts empty language And we have to make sure that TM does not except any string. My questions are:

• in formal description of TM I have read that input alphabet can't be empty then how a machine can except empty input?
• if we have a machine which accepts empty string then "how it is undecidable?"When we can simply reject any non-empty string?

If I have wrong concept or messed it kindly correct it