Online commerce refers to the buying and selling of goods and services over the internet, while retail commerce refers to the traditional brick-and-mortar stores where customers can physically visit and make purchases. Online commerce offers the convenience of shopping from anywhere at any time, while retail commerce provides the opportunity for customers to see, touch, and try products before making a purchase. Online commerce often involves lower overhead costs and can reach a wider audience, while retail commerce provides a more personalized and immediate shopping experience. **

A linear mapping, also known as a linear transformation, is a function between two vector spaces that preserves the operations of vector addition and scalar multiplication. In other words, it maps a vector from one space to another in a way that maintains the structure of the vector space. Linear mappings are fundamental in linear algebra and are used to describe various mathematical concepts and relationships in a geometrically meaningful way. They play a crucial role in solving systems of linear equations, studying eigenvalues and eigenvectors, and understanding the properties of matrices. **

MIDI mapping allows users to assign specific MIDI messages to control parameters within a software or hardware device. This process involves selecting a parameter to be controlled, such as volume or effects, and then assigning a MIDI message, such as a note, controller, or program change, to that parameter. Once the mapping is set up, the MIDI message can then be sent from a MIDI controller, such as a keyboard or pad controller, to manipulate the assigned parameter in real-time. This allows for a more hands-on and customizable approach to controlling music software and hardware. **

A mapping is proportional when there is a constant ratio between the corresponding values of the two sets being mapped. In other words, if the ratio of the output values to the input values remains constant, then the mapping is considered proportional. This means that as one set of values increases or decreases, the other set of values changes in direct proportion. **

Yes, the mapping is left-unique. This means that each input value in the domain is associated with only one output value in the range. In other words, no two different input values can map to the same output value. This ensures that the mapping is well-defined and unambiguous. **

An identical mapping is a type of mapping where each element in one set is paired with a unique element in another set, such that the pairing preserves the identity of the elements. In other words, each element in the first set corresponds to only one element in the second set, and vice versa. This type of mapping is often used in mathematics and computer science to establish a one-to-one correspondence between elements of two sets. **

A bijective mapping is a function between two sets that is both injective and surjective. In other words, every element in the domain is paired with a unique element in the codomain, and every element in the codomain is paired with at least one element in the domain. This means that there is a one-to-one correspondence between the elements of the two sets. Bijective mappings are also known as one-to-one and onto functions. **

Online shopping has certainly had an impact on retail stores, as it has changed consumer behavior and shopping habits. Many traditional brick-and-mortar stores have struggled to compete with the convenience and variety offered by online shopping. However, it's important to note that online shopping has also created new opportunities for retailers to reach customers and expand their businesses. While some retail stores have closed due to the rise of online shopping, others have adapted by offering online options and enhancing their in-store experiences to remain competitive. Overall, online shopping has transformed the retail landscape, but it hasn't necessarily destroyed retail stores entirely. **