twohandle

Twohandle is a term used in different contexts and can refer to more than one concept depending on the field. In hardware contexts, a two-handle faucet is a mixing faucet that uses separate levers for hot and cold water, allowing the user to adjust temperature and flow by combining the two streams inside the fixture.

In mathematics, two-handle (often written 2-handle) denotes a standard component in the handlebody decomposition of manifolds. A 2-handle is attached along a circle on the boundary of a manifold, typically modeled as D^2 × D^2, and the attachment is guided by a framing. Adding or removing 2-handles is a fundamental operation in the study and classification of smooth 4-manifolds, as it changes the topology of the space.

In other domains, Twohandle may appear as a brand name, product model, or project title, where the term is chosen for branding rather than to convey a specific technical meaning. Because of this variability, the exact definition of Twohandle is context-dependent and should be inferred from the surrounding field or documentation.

Overview of related concepts includes the general notion of a handle in topology, where higher- or lower-index handles generalize the idea of attaching cells to build up or modify spaces, and the practical considerations of faucet design in plumbing, where two handles offer traditional, tactile control over hot and cold streams. See also 2-handle, handle theory, and two-handle faucets for related topics.