Yesterday I got "The Telehraph" newspaper and was examining the puzzles section when caught a sentence: "Solutions published tomorrow". Is this a correct construction? Or maybe newspaper's slang?
This is an example of JOURNALESE.
According to Merriam-Webster's Dictionary
: a style of writing held to be characteristic of newspapers
In newspaper headlines it's typical to use the Past Participle for traditional passive constructions (in your case: ''published'' instead of 'will be published') or the bare Infinitive for traditional active constructions (for example: the headline ''President visit Germany tomorrow'' instead of 'The President will visit Germany tomorrow').