Turbomachine component or collection of components and associated turbomachine

A turbomachine comprising a part or set of parts comprising:

• at least first and second blades, and a platform from which the first and second blades extend, wherein
• the platform has, between an intrados of the first blade and an extrados of the second blade, a non-axisymmetric surface defining fins with a substantially triangular section extending downstream of a leading edge of each of the first and second blades, every fin being associated with a leading position and a trailing position on the surface between which the fin extends, such that:
• the leading position is located at between 5% and 35% of a relative length of a chord of the first or second blade extending from a leading edge to a trailing edge of the first or second blade;
• the larger the distance between a fin and the extrados of the second blade, the more the leading position of said fin is axially separated from the leading edge of the first and second blades.