Equivalent quantities refer to different measures or values that represent the same amount or concept in various forms. In different contexts, the term can have specific meanings: 1. **Mathematics**: In mathematics, equivalent quantities can refer to quantities that are equal to each other, such as fractions, percentages, or algebraic expressions. For example, \( \frac{1}{2} \) and \( 50\% \) are equivalent quantities since they represent the same portion of a whole.

Quantum mechanics in fiction typically refers to the incorporation of principles and concepts from quantum physics into narrative storytelling. This can take many forms, ranging from science fiction explorations of quantum concepts to more abstract or metaphorical uses of quantum ideas in literature and film.

Mechanical puzzles are physical puzzles that typically involve manipulating parts or components to achieve a specific goal or solve a problem. These puzzles often require reasoning, dexterity, and spatial awareness. They can take many forms, including: 1. **Disentanglement Puzzles**: These consist of several interlinked pieces that need to be separated. Examples include metal wire puzzles or string puzzles. 2. **Assembly Puzzles**: These require the assembly of various pieces into a complete shape or object.

Scale model collections refer to a hobby or practice where individuals create, collect, or display miniature representations of real-world objects, structures, vehicles, or figures. These models are usually crafted at a specific scale, meaning the model is a reduced-size version of the actual object.

North Macedonia is divided into statistical regions that are primarily used for statistical purposes and to facilitate regional development. As of the latest data, North Macedonia is divided into the following eight statistical regions: 1. **Skopje Region**: This is the capital region, encompassing the city of Skopje and surrounding municipalities. 2. **Vardar Region**: Located in the central part of the country, this region includes the city of Veles and is known for its agricultural and industrial output.

The term "Physicists from the Republic of Geneva" likely refers to a historical context related to the significant contributions of scientists from Geneva, particularly during the Enlightenment and the development of modern physics. Geneva has a rich history of intellectual and scientific achievement, being home to notable figures such as: - **George Biddell Airy**: An astronomer who made significant contributions to the field of optics and the study of light.

In group theory, the term "core" can refer to a specific concept related to the notion of a normal subgroup. The core of a subgroup \( H \) of a group \( G \), often denoted as \( \text{Core}_G(H) \), is defined as the largest normal subgroup of \( G \) that is contained within \( H \).