Conjugate ser in El Presente de Subjuntivo (present subjunctive)

Hola Ralph

With verb creer in negative we can use both the infinitive or the subjunctive (even if it is the same subject). You could say:

"Yo no creo ser muy egoista" (I don't think I am very selfish)

or

"Yo no creo que sea muy egoista" (I don't think I am very selfish)

(The second sentence is more commonly used)

The rule about using the infinitive instead of the subjunctive, when having the same subject  doesn't apply to all verbs. 

With "wish" verbs like querer, this rule if fixed:

Yo quiero ir a Madrid (same subject, infinitive)

Yo quiero que tú vayas a Madrid (different subject, subjunctive)

But it is not the same case with "creer". 

I hope this helps,

Inma

Good question! 

Consider these shorter phrases:

We are the only ones (ser)

vs 

We are in the restaurant (estar)

The verb is expressing "being" about "being the only people" which is independent of what follows (which happens to be a location). You could write the sentence in a longer form, We are the only people [who are] in the restaurant to see there are two 'being' verbs implied, in fact.

It might be tempting to still think estar is the right verb choice, since 'being the only ones' is temporary state, but, in fact, 'only' is a modifier and as such a red-herring too! Really, that sentence boils down to talking about people: We are the [optional modifer] people...

I think this is the closest rule:

https://spanish.kwiziq.com/revision/grammar/use-ser-not-estar-to-introduce-people 

I'll double check with one of our Spanish native linguists to be sure though.

Hi Nick

Gruff's explanation is spot on. This "ser" is identifying, not talking about the position/location. Other practical examples where we use ser in this same way to identify are for example when someone knocks on the door and before you open it you ask: "¿Quién es?" (Who is it?), and the other person answers "Soy yo, Luis" (It's me, Luis). Or when you are playing a game and you win and then say "¡Yo soy el ganador!" (I am the winner!). All these are using ser to identify.

Saludos,

Inma

Many thanks for the quick and well explained reply!