Can the preposition "ab" be used with the future tense as well?
Normally I'd think one'd hear:

Ich bin ab Montag in Rom.

Aber kann man auch sagen:

Ich werde ab Montag in Rom sein.

Question

Can the preposition "ab" be used with the future tense as well?
Normally I'd think one'd hear:

Ich bin ab Montag in Rom.

Aber kann man auch sagen:

Ich werde ab Montag in Rom sein.

Answer

Ja, kann man!
Die grammatikalische Zukunftsform Futur I: "Ich werde ab Montag in Rom sein."
Das Deutsche lässt aber auch das 'Präsens des Zukünftigen' zu:
Ich bin ab Montag in Rom.
http://www.canoo.net/services/OnlineGrammar/Wort/Verb/Tempora/Praesens.html?lang=en#Anchor-47857

In English the same: Simple Present for Future Events, e.g. The plane arrives at 18.00 tomorrow.

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