# Mathematical symbol as simple predicate

I am translating a paper about a general physics question. I am not very familiar with physics other than the historical perspective and I am requesting some help with the grammar. I have a sentence that translates perfectly from the original Spanish as follows:

“At the moment of t1 at which both objects reach the ground, y1(t1)=y2(t1)=0.”

In English, a complete sentence requires a subject and a predicate. In the above sentence, the subject would be “y1(t1)”, which I guess I don´t have a problem with. My query is regarding the simple predicate, which in this case would be “=”. All of the English words in this sentence amount to prepositional phrases.

Is this standard use of language in scientific documents in English? Should I change the sentence to read something like, “The formula y1(t1)=y2(t1)=0 is satisfied at the moment…”?

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I think that the only problem with your sentence is "At the moment of t1". I would drop "of" and simply say "At the moment t1...". The rest of the sentence looks and sounds fine to me, but then I'm not a native speaker :) – Armen Ծիրունյան Dec 23 '12 at 21:53
The "=" in the equation can play the role of the verb, which means this translation is fine (except, as @Armen recommends, I'd drop the "of"). – Peter Shor Dec 23 '12 at 21:57
The symbol '=' in an equation is pronounced equals (always singular present) /'ikwəlz/. The whole equation is pronounced /'waywən əv 'tiwən 'ikwəlz 'waytu əv 'tiwən 'ikwəlz 'zɪro/. The subscripts should be printed sub-, however; i.e, y₁(t₁) = y₂(t₁) = 0. Oh, yes, and no of, as pointed out. – John Lawler Dec 23 '12 at 22:02
Also see “Four plus two equals six” (or “is equal to six” or “is six”)about how to read “4 + 2 = 6”. – jwpat7 Dec 23 '12 at 22:45
'At time t₁' would be more usual than 'at moment t₁'. – Edwin Ashworth Dec 23 '12 at 23:00