A Markov chain is a discrete random process with the property that the next state depends only on the current state (wikipedia). A Markov chain is a discrete random process with the property that the next state depends only on the current state (wikipedia). So $P(X_n | X_1, X_2, \ldots X_n-1) = P(X_n | X_{n-1})$.
Some people find molecules and compounds confusing. Here's how to remember the difference. If you join two different chemical elements together, you can often make a completely new substance. Glue two atoms of hydrogen to an atom of oxygen and you'll make a single molecule of water.
A molecule is formed when two or more atoms of an element chemically join together. If the types of atoms are different from each other, a compound is formed. Not all molecules are compounds, since some molecules, such as hydrogen gas or ozone, consist only of one element or type of atom. molecule is formed when two or more atoms of an element chemically join together. If the types of atoms are different from each other, a compound is formed. Not all molecules are compounds, since some molecules, such as hydrogen gas or ozone, consist only of one element or type of atom.