What is "advice"

Advice \Ad*vice"\, n. [OE. avis, F. avis; ? + OF. vis, fr. L. visum seemed, seen; really p. p. of videre to see, so that vis meant that which has seemed best. See Vision, and cf. Avise, Advise.]

1. An opinion recommended or offered, as worthy to be followed; counsel.

   We may give advice, but we can not give conduct.
   --Franklin.

2. Deliberate consideration; knowledge. [Obs.]

   How shall I dote on her with more advice, That thus without advice begin to love her?
   --Shak.

3. Information or notice given; intelligence; as, late advices from France; -- commonly in the plural.

   Note: In commercial language, advice usually means information communicated by letter; -- used chiefly in reference to drafts or bills of exchange; as, a letter of advice.
   --McElrath.

4. (Crim. Law) Counseling to perform a specific illegal act. --Wharton. Advice boat, a vessel employed to carry dispatches or to reconnoiter; a dispatch boat. To take advice.

   1. To accept advice.

   2. To consult with another or others.

      Syn: Counsel; suggestion; recommendation; admonition; exhortation; information; notice.

late 13c., auys "opinion," from Old French avis "opinion, view, judgment, idea" (13c.), from phrase ço m'est à vis "it seems to me," or from Vulgar Latin *mi est visum "in my view," ultimately from Latin visum, neuter past participle of videre "to see" (see vision).\n

\nThe unhistorical -d- was introduced in English 15c., on model of Latin words in ad-. Substitution of -c- for -s- is 18c., to preserve the breath sound and to distinguish from advise. Meaning "opinion given as to action, counsel" is from late 14c.

n. 1 An opinion recommended or offered, as worthy to be followed; counsel. 2 (context obsolete English) Deliberate consideration; knowledge. 3 Information or notice given; intelligence; as, late advices from France; commonly in the plural. In commercial language, advice usually means information communicated by letter; used chiefly in reference to drafts or bills of exchange; as, a letter of advice. 4 (context legal English) Counseling to perform a specific illegal act. 5 (context computing programming English) In aspect-oriented programming, the code whose execution is triggered when a join point is reached.

n. a proposal for an appropriate course of action

Advice (noun) or advise (verb) may refer to:

• Advice (opinion), an opinion or recommendation offered as a guide to action, conduct
  • Advice column, a regular feature on a website or in a newspaper or magazine
  • Academic advising, in academics
  • Legal advice, the giving of a formal and binding opinion regarding the substance or procedure of the law
• Advice (constitutional), in constitutional law, a frequently binding instruction issued to a constitutional office-holder
• Advice (programming), a piece of code executed when a join point is reached
• Advice (complexity), in complexity theory, a string with extra information used by Turing machine or other computing device
• Pay advice, also known as a pay slip
• Advice (song), a debut single by Christina Grimmie
• ADVISE (Analysis, Dissemination, Visualization, Insight, and Semantic Enhancement), a research and development program within the United States Department of Homeland Security
• ADVISE Advanced Stochastic Modelling Software from Conning & Company

Advice, in constitutional law, is formal, usually binding, instruction given by one constitutional officer of state to another. Especially in parliamentary systems of government, heads of state often act on the basis of advice issued by prime ministers or other government ministers. For example, in constitutional monarchies, the monarch usually appoints Ministers of the Crown on the advice of his or her prime minister.

Among the most prominent forms of advice offered are:

• Advice to appoint and remove individual ministers.
• Advice to dissolve parliament.
• Advice to deliver formal statements, such as a speech from the throne.

In some states, the duty to accept advice is legally enforceable, having been created by a constitution or statute. For example, the Basic Law of Germany requires the President to appoint federal ministers on the advice of the Chancellor. In others, especially under the Westminster system, advice may legally be rejected; for example, in several Commonwealth realms, the Queen is not legally obliged to accept the advice of her ministers. This lack of obligation forms part of the basis for the Queen's reserve powers. Nevertheless, the convention that the head of state accept ministerial advice is so strong that in ordinary circumstances, refusal to do so would almost certainly provoke a constitutional crisis.

Although most advice is binding, in comparatively rare instances, it is not. For example, many heads of state may choose not to follow advice on a dissolution of parliament where the government has lost the confidence of that body. In some cases, whether the advice is mandatory or truly just advisory depends on the context and authority of the person offering it. Hence the President of Ireland ordinarily is obliged to dissolve Dáil Éireann (the House of Representatives) when advised to do so by the Taoiseach (prime minister). However, where a taoiseach has (in the words of the Constitution of Ireland) "ceased to retain the support of a majority in Dáil Éireann" (i.e., lost the confidence of parliament) the President has the option of refusing to follow that advice.

Advice (also called exhortation) is a form of relating personal or institutional opinions, belief systems, values, recommendations or guidance about certain situations relayed in some context to another person, group or party often offered as a guide to action and/or conduct. Put a little more simply, an advice message is a recommendation about what might be thought, said, or otherwise done to address a problem, make a decision, or manage a situation.

In computational complexity theory, an advice string is an extra input to a Turing machine that is allowed to depend on the length n of the input, but not on the input itself. A decision problem is in the complexity class P/f(n) if there is a polynomial time Turing machine M with the following property: for any n, there is an advice string A of length f(n) such that, for any input x of length n, the machine M correctly decides the problem on the input x, given x and A.

The most common complexity class involving advice is P/poly where advice length f(n) can be any polynomial in n. P/poly is equal to the class of decision problems such that, for every n, there exists a polynomial size Boolean circuit correctly deciding the problem on all inputs of length n. One direction of the equivalence is easy to see. If, for every n, there is a polynomial size Boolean circuit A(n) deciding the problem, we can use a Turing machine that interprets the advice string as a description of the circuit. Then, given the description of A(n) as the advice, the machine will correctly decide the problem on all inputs of length n. The other direction uses a simulation of a polynomial-time Turing machine by a polynomial-size circuit as in one proof of Cook's Theorem. Simulating a Turing machine with advice is no more complicated than simulating an ordinary machine, since the advice string can be incorporated into the circuit.

Because of this equivalence, P/poly is sometimes defined as the class of decision problems solvable by polynomial size Boolean circuits, or by polynomial-size non-uniform Boolean circuits.

P/poly contains both P and BPP (Adleman's theorem). It also contains some undecidable problems, such as the unary version of every undecidable problem, including the halting problem. Because of that, it is not contained in DTIME (f(n)) or NTIME (f(n)) for any f.

Advice classes can be defined for other resource bounds instead of P. For example, taking a non-deterministic polynomial time Turing machine with an advice of length f(n) gives the complexity class NP/f(n). If we are allowed an advice of length 2, we can use it to encode whether each input of length n is contained in the language. Therefore, any boolean function is computable with an advice of length 2 and advice of more than exponential length is not meaningful.

Similarly, the class L/poly can be defined as deterministic logspace with a polynomial amount of advice.

Known results include:

• The classes NL/poly and UL/poly are the same, i.e. nondeterministic logarithmic space computation with advice can be made unambiguous. This may be proved using an isolation lemma.
• It is known that coNEXP is contained in NEXP/poly.
• If NP is contained in P/poly, then the polynomial time hierarchy collapses ( Karp-Lipton theorem).

In aspect and functional programming, advice describes a class of functions which modify other functions when the latter are run; it is a certain function, method or procedure that is to be applied at a given join point of a program.

The following is taken from a discussion at the mailing list aosd-discuss. Pascal Costanza contributed the following:

The term advice goes back to the term advising as introduced by Warren Teitelman in his PhD thesis in 1966. Here is a quote from Chapter 3 of his thesis:

"Advising" found its way into BBN Lisp and later into Xerox PARC's Interlisp.

It also found its way to Flavors, the first object-oriented extension to Lisp developed at MIT. They were subsumed under the notion of method combination. See, for example, AIM-602 at http://www.ai.mit.edu/research/publications/browse/0600browse.shtml

Since method combination and macros are closely related, it's also interesting to note that the first macro system was described in 1963, three years before Warren Teitelman's PhD thesis. See AIM-57 at http://www.ai.mit.edu/research/publications/browse/0000browse.shtml