全ぜん単たん射しゃ

noun

bijection

Technical term in mathematics for a function that is both injective (one-to-one) and surjective (onto).

• 全ぜん単たん射しゃが存そん在ざいするとき、二ふたつの集しゅう合ごうは同おなじ濃のう度どを持もつ。

  When a bijection exists, the two sets have the same cardinality.