Figure 3   In Axiom 1, each inertial frame can be described by unit quantities, such as 1, 2, 4, etc. Although the ratio is 2:1, the units are different (b is in 4 units, and c is in 8 units), so the proportional extension of the units differs and cannot replace or offset each other.
 
Principle of universal invariant velocity for Axiom 1 In Axiom 1, each quantity is a specific quantity, that is, it is itself rather than any other quantity. Thus, we reasonably conclude that, in Axiom 1, any velocity is itself, not any other velocity (where the essence of the concept of velocity is single-dimensional space or time). Each velocity is thus constant relative to other velocities, not just the velocity of light. This property is defined as the principle of universal velocity invariance for Axiom 1.
 
5 Velocity is one-dimensional
 
Common misconceptions about velocity can be cleared up using these two principles.
(1)Velocity is two-dimensional, and there is an instantaneous velocity going to the infinite distance. Here space and time are independent of each other, that is, a certain moment of the clock corresponds to any distance or position in space. For example, 1 second corresponds to any length, which is the Newtonian absolute space-time view. Because a moment of a clock corresponds to any distance or position in space, this means that velocity is variable, that is,, the size of one velocity depends on how much it corresponds to other velocity, and velocity can be added or reduced. Therefore, the concept of a specific velocity does not exist here. The single-dimensional properties and universal-velocity-invariant properties of Axiom 1 deny the correctness of this concept. This property is essentially two-dimensions-without-size Axiom 1, which means that a Galilean transformation is meaningless.
(2) Velocity is two-dimensional and can be compared in size, in which there is no instantaneous velocity extending to infinity, and the velocity of light is a finite magnitude of velocity that is also a limit velocity. Here, the principle of relativity can be applied. Because the invariability of the velocity of light (i.e., it remains constant for Cartesian coordinates at any velocity) has been experimentally confirmed, the velocity of light has a privileged position as the basis for defining space and time (i.e., light time and light space), which is known as relativistic space-time. Here, one second of the clock corresponds to a space length of only 300,000 kilometers (i.e., 1 second is equivalent to 300,000 kilometers), two seconds corresponds to 600,000 km (i.e., 2 seconds is equivalent to 600,000 kilometers), and so on. Here, 1 second does not correspond to other distances, such as 3 meters. Therefore, the notion of a velocity of 3 m/s (i.e., 1 second is equivalent to 3 meters) makes no sense with relativity. Speed events of 3 m/s are given in light time and in light space (Figure 3). As a result, the space-time properties of two inertial systems K 'and K (for example, an inertial system with a velocity of 3 m/s is compared with an inertial system with a velocity of 0) have the following characteristics. From the observation of K', the time of K is prolonged, and the space is shortened. As observed from K, the time of K' is shortened and the space is elongated (Figure 4). The single-dimensional nature of Axiom 1 and the infinity of space-time deny the correctness of this concept.