Periodicity is demonstrated by the repeating patterns or trends that occur at regular intervals in a specific set of data or elements. This can be seen in the periodic table of elements, where elements are arranged in order of increasing atomic number and show similar chemical properties at regular intervals. In mathematics, periodicity is shown in functions that repeat their values at regular intervals, such as sine and cosine functions. Overall, periodicity is a fundamental concept that helps us understand and predict patterns in various disciplines. **

Periodicity can be shown by identifying a repeating pattern or trend in a set of data or a physical phenomenon. This can be done by graphing the data and looking for regular peaks and troughs, or by analyzing the data for consistent intervals or cycles. In the case of physical phenomena, periodicity can be demonstrated by observing the regular occurrence of a certain behavior or event at predictable intervals. Additionally, mathematical tools such as Fourier analysis can be used to identify and quantify periodic patterns in data. **

The periodicity of a sequence refers to the length of the shortest repeating pattern within the sequence. In other words, it is the number of terms in the sequence before it starts to repeat itself. For example, in a sequence like 1, 2, 3, 1, 2, 3, the periodicity is 3 because the pattern 1, 2, 3 repeats every 3 terms. Understanding the periodicity of a sequence can help in identifying patterns and predicting future terms in the sequence. **

The caricature of the summit conference in Helsinki shows the leaders of the United States and Russia, Donald Trump and Vladimir Putin, sitting at a table with Trump holding a puppet string attached to Putin. This caricature is a satirical representation of the perception that Trump is under the control or influence of Putin, suggesting that Putin is pulling the strings and manipulating Trump. The image reflects the controversy and speculation surrounding the relationship between the two leaders and the potential influence of Russia on the United States. **

A symposium is a formal gathering or meeting where experts in a particular field come together to discuss and exchange ideas on a specific topic. It is often organized as a series of presentations, panel discussions, and Q&A sessions, allowing participants to share their knowledge and insights with each other. Symposia are commonly held in academic and professional settings, providing a platform for networking, collaboration, and learning within a specific discipline or industry. **

"Der Kongress tanzt" is a German phrase that translates to "The Congress Dances" in English. The phrase originated from the Congress of Vienna in 1814-1815, where European diplomats and leaders gathered to reorganize Europe after the Napoleonic Wars. The phrase is a metaphor for the diplomatic and political maneuvering that took place during the Congress, likening it to a dance where participants carefully navigated their relationships and alliances. It reflects the complex and intricate nature of international diplomacy and negotiations during this historic event. **

A convention is a formal agreement or a set of accepted norms and practices that govern behavior in a particular context or industry. It is a customary way of doing things that is widely recognized and followed by a group of people. Conventions help to establish consistency, order, and predictability in social interactions or professional settings. They can vary across different cultures, societies, or fields of study. **

The G20 summit is a meeting of the leaders of the world's 20 largest economies, representing both developed and developing countries. The summit provides a platform for these leaders to discuss and coordinate on global economic issues, such as trade, finance, and development. It is an opportunity for countries to work together to address common challenges and promote global economic stability and growth. The G20 summit also serves as a forum for leaders to address pressing international issues, such as climate change, terrorism, and global health crises. **