In any trend at any level, a complete trend type contains at least two trend centers in the same direction in turn, which is called the trend at that level. That is, the two trend centers at the same level before and after are equivalent to rising and its continuation in DD & gtPre-GG. Constantly produce new trend centers, and form trends around fluctuations without overlapping.

Central extension: after the trend center is formed, at least one of the two sub-level fluctuations around the trend center touches the trend center interval, and its mathematical expression is: Zn and ZG-ZD interval overlap. (Zn is all secondary trend types consistent with the central direction)

Expansion center: refers to the last sub-level trend after the formation of the center, and the subsequent sub-level trends return to the center. That is to say, after the last line segment leaves the center, the following line segments return to the center.

The main points of the center expansion are summarized as follows:

1. Relationship among this level, advanced level and sub-level: The expansion of this level hub to a higher level hub requires at least 9 continuous sub-level trends at this level.

Theorem 1: The extension of the trend center is equivalent to the overlap of any interval [dn, gn] and [ZD, ZG]. In other words, if there is Zn, DN >；; ZG or gn will inevitably produce a high trend center or trend and continuation.

Trend Decomposition Theorem 2: Any trend type at any level is composed of at least three sub-level trend types.

Reasoning process: Take the simplest 1f (1min) hub as an example. A 5f(5) hub, according to the definition of hub, is composed of at least three continuous 1f trend types. According to the second theorem of trend decomposition, a trend of 1f consists of at least three line segments, three of which are nine.

2. The extension of this level center to a higher level center is formed by the continuous extension of this level center or the overlapping fluctuation intervals of two adjacent level centers.

This requirement is also obvious. Not all nine consecutive segments are hub expansion, but nine consecutive segments can also be a trend at this level. Therefore, only nine or more continuous sub-level trends of the same level can be decomposed and combined into at least three continuous sub-level trends of the same level, and the three continuous sub-level trends have overlapping parts to meet the requirements of hub expansion. To meet this requirement, this level hub can only be formed by one of the ways that this level hub continues to extend or the fluctuation intervals of two adjacent level hubs overlap.

Pivot expansion: if the overlapping interval of three consecutive sub-level trend types does not overlap with the previous trend center, but the fluctuation around the center touches a certain instantaneous fluctuation interval when the previous trend center continues, the trend type cannot be considered as a trend, but only produces a trend center with a higher level.

The extension of the trend center and the continuous emergence of new trend centers do not overlap with the corresponding trends around fluctuations. In these two cases, it is certainly impossible to form a larger level of trend center. In order to form a trend center with a large level, it is necessary to take measures that the fluctuations around the new trend center with the same level overlap with certain fluctuation intervals around the previous center.

Before a trend center is completed, its fluctuation touches the previous trend center or an instantaneous fluctuation interval when it is extended, thus producing a higher-level trend center.

Trend level continuation theorem 2: the trend center of a larger level is generated if and only if the fluctuation intervals generated around two consecutive trend centers of the same level overlap.

Central expansion has two results. The first is that there is an expanding third trading point due to the expansion of the center, and the second is that the expansion of the center leads to a greater degree of center.

In practice, you can overlap a subcategory every three strokes or every three paragraphs: (as shown in the figure below)

First (pen) is established every three high points, every three low points, and then from low to high, from high to low, which is the pen expansion and expansion center interval.

Second, (line segment) every three high points are established, every three low points are established, and then the high takes the low and the low takes the high, which is the extension of the line segment.

In practice, we can connect the highest point and lowest point of every three intervals of each center as a K-line, so that nine intervals form three centers and three centers become three K-lines, and then the overlapping part of these three K-lines can be considered as the central interval of expansion and expansion. In this way, we can see at a glance how the hub expands, or how it expands into a high-level trend hub.

The definition of class center:

When the trend is only three paragraphs, it is called the class center. It can also be understood that the quasi-hub is similar to a hub with unfinished line segments. Then since there is a class center, there is a class trend and a class consolidation type. The quasi-central representative is very strong in a certain direction, rarely pauses and hesitates, and is basically a straightforward and strong operation in the original direction. Unlike the standard central morphology, the structure is a little more complicated and the pause time is a little longer.

Key points and difficulties:

1, what's the trend?

2. How did the center expand from 1f (1min) to 5f to 30f?

3. What is the relationship between center, line segment and pen?

3. Class center