- In mathematics, a binary operation is commutative if changing the order of the operands does not change the result.
- Associative property (Wikipedia)
In mathematics, the associative property is a property of some binary operations, which means that rearranging the parentheses in an expression will not change the result. In propositional logic, associativity is a valid rule of replacement for expressions in logical proofs.
- Star Tales - Carina (ianridpath.com)
The smallest but most prominent of the three parts into which the ancient Greek constellation of Argo Navis, the ship of the Argonauts, was divided by the French astronomer Nicolas Louis de Lacaille in his first catalogue of the southern stars, published in 1756. In that catalogue he gave it the French name Corps du Navire. His final catalogue, Coelum australe stelliferum, appeared in 1763 containing the same three subdivisions but with Latin instead of French names. Although usually described as the keel, Carina represents the main body or hull of the ship. The other two parts are Puppis, the poop or stern, and Vela, the sails.