Working in a shared office means keeping track of your own supplies. You already know that in European Portuguese, possessives usually require a definite article, as in o meu agrafador (my stapler). However, there are two common situations where we drop this article entirely.
"This is mine" (After the verb ser)
When stating that something belongs to someone directly after the verb ser (to be), you omit the definite article. The possessive acts as an adjective describing the subject.
Instead of saying Este agrafador é o meu, you simply say Este agrafador é meu.
| This stapler is mine, but the headphones are yours. | Este agrafador é meu, mas os auscultadores são teus. |
This applies to all possessive pronouns (meu, teu, nosso, vosso, etc.) and works no matter who owns the item.
| Perhaps that hole punch is yours, since the stapler is ours. | Se calhar esse furador é vosso, visto que o agrafador é nosso. |
| I am going to use the box cutter, because this highlighter is not mine. | Vou usar o x-ato, porque este sublinhador não é meu. |
"A [noun] of mine" (Indefinite possessions)
The second exception happens when you are talking about an indefinite possession — like "a paperclip of mine" rather than "my paperclip."
To form this, use the indefinite article (um, uma, uns, umas), the noun, and then the possessive directly after it. Since you are already using an indefinite article, you cannot use a definite article at the same time.
| Do you see a paperclip of mine on top of the notepad? | Vês um clipe meu em cima do bloco de notas? |
Notice how the possessive (meu, tua, etc.) still follows the noun and matches its gender and number.
| Perhaps a flash drive of yours is under the notepad. | Se calhar uma pen drive tua está debaixo do bloco de notas. |
| Is that box cutter yours? I am looking for a calculator of mine. | Esse x-ato é teu? Eu procuro uma calculadora minha. |