To be announced (TBA), to be confirmed (TBC), and to be determined (or to be decided, TBD) are placeholder terms used very broadly in event planning to indicate that although something is scheduled or expected to happen, a particular aspect of that remains to be arranged or confirmed.
These phrases are similar, but may be used for different degrees of indeterminacy:
Other similar phrases sometimes used to convey the same meaning, and using the same abbreviations, include "to be ascertained", "to be arranged", "to be advised", "to be adjudicated", "to be done", "to be decided", and "to be declared".
Use of the abbreviation "TBA" is formally reported in a reference work at least as early as 1955, and "TBD" is similarly reported as early as 1967.
In computing, ANSI escape codes (or escape sequences) are a method using in-band signaling to control the formatting, color, and other output options on video text terminals. To encode this formatting information, certain sequences of bytes are embedded into the text, which the terminal looks for and interprets as commands, not as character codes.
ANSI codes were introduced in the 1970s and became widespread in the minicomputer/mainframe market by the early 1980s. They were used by the nascent bulletin board system market to offer improved displays compared to earlier systems lacking cursor movement, leading to even more widespread use.
Although hardware text terminals have become increasingly rare in the 21st century, the relevance of the ANSI standard persists because most terminal emulators interpret at least some of the ANSI escape sequences in the output text. One notable exception is the win32 console component of Microsoft Windows.
Almost all manufacturers of video terminals added vendor-specific escape sequences to perform operations such as placing the cursor at arbitrary positions on the screen. One example is the VT52 terminal, which allowed the cursor to be placed at an x,y location on the screen by sending the ESC
character, a y
character, and then two characters representing with numerical values equal to the x,y location plus 32 (thus starting at the ASCII space character and avoiding the control characters).
TBC may refer to:
In universal algebra and in model theory, a structure consists of a set along with a collection of finitary operations, and relations that are defined on it.
Universal algebra studies structures that generalize the algebraic structures such as groups, rings, fields and vector spaces. The term universal algebra is used for structures with no relation symbols.
Model theory has a different scope that encompasses more arbitrary theories, including foundational structures such as models of set theory. From the model-theoretic point of view, structures are the objects used to define the semantics of first-order logic. For a given theory in model theory, a structure is called a model, if it satisfies the defining axioms of that theory, although it is sometimes disambiguated as a semantic model when one discusses the notion in the more general setting of mathematical models. Logicians sometimes refer to structures as interpretations.
In database theory, structures with no functions are studied as models for relational databases, in the form of relational models.
In mathematics, progress often consists of recognising the same structure in different contexts - so that one method exploiting it has multiple applications. In fact this is a normal way of proceeding; in the absence of recognisable structure (which might be hidden) problems tend to fall into the combinatorics classification of matters requiring special arguments.
In category theory structure is discussed implicitly - as opposed to the explicit discussion typical with the many algebraic structures. Starting with a given class of algebraic structure, such as groups, one can build the category in which the objects are groups and the morphisms are group homomorphisms: that is, of structures on one type, and mappings respecting that structure. Starting with a category C given abstractly, the challenge is to infer what structure it is on the objects that the morphisms 'preserve'.
The term structure was much used in connection with the Bourbaki group's approach. There is even a definition. Structure must definitely include topological space as well as the standard abstract algebra notions. Structure in this sense is probably commensurate with the idea of concrete category that can be presented in a definite way - the topological case means that infinitary operations will be needed. Presentation of a category (analogously to presentation of a group) can in fact be approached in a number of ways, the category structure not being (quite) an algebraic structure in its own right.
The structure of a thing is how the parts of it relate to each other, how it is "assembled".
Structure may also refer to:
In architecture:
In engineering:
In art:
In biology:
In chemistry: