Nondeterministic finite automatonIn automata theory, a finite-state machine is called a deterministic finite automaton (DFA), if each of its transitions is uniquely determined by its source state and input symbol, and reading an input symbol is required for each state transition. A nondeterministic finite automaton (NFA), or nondeterministic finite-state machine, does not need to obey these restrictions. In particular, every DFA is also an NFA. Sometimes the term NFA is used in a narrower sense, referring to an NFA that is not a DFA, but not in this article.
Femoral veinIn the human body, the femoral vein is the vein that accompanies the femoral artery in the femoral sheath. It is a deep vein that begins at the adductor hiatus (an opening in the adductor magnus muscle) as the continuation of the popliteal vein. The great saphenous vein (a superficial vein), and the deep femoral vein drain into the femoral vein in the femoral triangle when it becomes known as the common femoral vein. It ends at the inferior margin of the inguinal ligament where it becomes the external iliac vein.
String operationsIn computer science, in the area of formal language theory, frequent use is made of a variety of string functions; however, the notation used is different from that used for computer programming, and some commonly used functions in the theoretical realm are rarely used when programming. This article defines some of these basic terms. A string is a finite sequence of characters. The empty string is denoted by . The concatenation of two string and is denoted by , or shorter by . Concatenating with the empty string makes no difference: .
Great saphenous veinThe great saphenous vein (GSV), or long saphenous vein; səˈfiːnəs) is a large, subcutaneous, superficial vein of the leg. It is the longest vein in the body, running along the length of the lower limb, returning blood from the foot, leg and thigh to the deep femoral vein at the femoral triangle. The great saphenous vein originates from where the dorsal vein of the big toe (the hallux) merges with the dorsal venous arch of the foot. After passing in front of the medial malleolus (where it often can be visualized and palpated), it runs up the medial side of the leg.
SubstringIn formal language theory and computer science, a substring is a contiguous sequence of characters within a string. For instance, "the best of" is a substring of "It was the best of times". In contrast, "Itwastimes" is a subsequence of "It was the best of times", but not a substring. Prefixes and suffixes are special cases of substrings. A prefix of a string is a substring of that occurs at the beginning of ; likewise, a suffix of a string is a substring that occurs at the end of .
TrieIn computer science, a trie (ˈtriː, ˈtraɪ), also called digital tree or prefix tree, is a type of k-ary search tree, a tree data structure used for locating specific keys from within a set. These keys are most often strings, with links between nodes defined not by the entire key, but by individual characters. In order to access a key (to recover its value, change it, or remove it), the trie is traversed depth-first, following the links between nodes, which represent each character in the key.
