Generally speaking, I want to say that x is equivalent to y but one is more succinct than the other, in a single word if possible (because ironically "more succinct" is not very succinct).
E.g: 4 is more succinct than 1+1+1+1.
I think "terser" fits your requirement. The word comes from the Latin, tergere meaning to wipe or polish, and the OED traces its original meaning as applied to language from generally polished and polite to the more particular -- concise, pithy.
I agree with Edwin that terse opens another can of worms. If it bothers you to say "more succinct", because it's two words, not one, then you might try rewriting your sentence, to use "succinctness". Example:
Formulation B is preferred over formulation A for its succinctness.