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Topic: Necessary and sufficient

	Necessary and Sufficient Conditions
		Although we can use the notion of necessary condition in defining what it is for something to be a sufficient condition (and vice versa), there is no straightforward way to give a precise and comprehensive account of the meaning of the term "necessary (or sufficient) condition" itself.
		Being an elephant is a sufficient condition of her having a trunk; having a trunk in turn is a necessary condition of Nellie's being an elephant.
		To specify the necessary conditions for the truth of the sentence "that figure is a square" is to specify a number of conditions including "that figure has four sides", "that figure is on a plane", and "that figure is closed".
	plato.stanford.edu /entries/necessary-sufficient (5423 words)

	More on Necessary and Sufficient Conditions
		Getting a total of 95% in this class is a sufficient condition for earning a final grade of A. If you have 95% for the course, then it must follow that you will have a final grade of A. Pouring a gallon of freezing water on my sleeping dog is sufficient to wake her up.
		Similiarly, it is not necessary for rain to be pouring from the sky for the ground to be wet.
		Being a male is a necessary condition for being a father since it is impossible to be a father without being a male.
	web.mala.bc.ca /clemotteo/more_on_necessary_and_sufficient.htm (1002 words)

	Voluntary Human Extinction: Necessary and Sufficient (Site not responding. Last check: 2007-10-20)
		However, if we assume that there are at least some animals who have sufficiently happy lives, then we should try to prevent this dismal outcome by any reasonable means, since any happy individuals (regardless of species) would be better than no happy individuals.
		Also, though many people assume and claim to have a strong desire for children, it is arguable that this desire could be societally imposed, and that humans free from the pressure to rear would come to enjoy greater lives.
		People who want to have children for decidedly selfish reasons (unconditional love, care and companionship in old age), would do well to note that offspring are often abysmal providers in these respects, and would find their needs better met in a dog.
	www.venge.net /wedding/extinction.html (2516 words)

	Necessary and sufficient ...
		A is a necessary condition of B if and only if B cannot occur without the occurrence of A. Example: Oxygen is a necessary condition for fire, but not sufficient.
		Sufficient conditions, instead, are enough to bring about a particular event or property.
		Being a bachelor is a _______________ condition for an unmarried adult male.
	web.mala.bc.ca /clemotteo/necessary_and_sufficient_conditiphil100fall2003.htm (173 words)

	Necessary - Wikipedia, the free encyclopedia
		Look up necessary on Wiktionary, the free dictionary.
		A necessary truth - Something that cannot fail to be true.
		This is a disambiguation page, a list of pages that otherwise might share the same title.
	en.wikipedia.org /wiki/Necessary (115 words)

	Conditionals, and necessary and sufficient conditions (Site not responding. Last check: 2007-10-20)
		A is a necessary condition of B if B could not be the case without A being the case.
		A is a sufficient condition of B if A could not be the case without B's being the case.
		On the weakest conceivable reading, A's being a necessary condition of B simply asserts the contingent truth of the material conditional "If B then A", and A's being a sufficient condition of B the contingent truth of the material conditional "If A then B".
	www.cogsci.ed.ac.uk /~ddb/teaching/vade-mecum/2-4.htm (774 words)

	Necessary and sufficient conditions (Site not responding. Last check: 2007-10-20)
		That means that D is a sufficient condition of C. You cannot win the election without receiving some votes.
		In general, it’s tempting to think about necessary and sufficient conditions in terms of causes and effects but that temptation should be resisted.
		In other words, A is a sufficient, but not a necessary, condition of B. Similarly, D is a sufficient, but not a necessary, condition of C. You can receive some votes (C) without winning the election (D), therefore, winning the election (D) cannot be a necessary condition of receiving some votes (C).
	humanities.uchicago.edu /faculty/mgreen/HumanRtsF04/Notes/NecessarySufficientConds.shtml (935 words)

	Further explanation of Necessary and Sufficient Conditions
		For example, while air is a necessary condition for human life, it is by no means a sufficient condition, i.e.
		air's being a necessary condition for human life) that show that a necessary condition is not (generally) a sufficient condition.
		"Being a father is a sufficient condition for being male, and being male is a necessary condition for being a father." (But being a father is not a necessary condition for being a male [e.g.
	www.sfu.ca /philosophy/w100a012.htm (1094 words)

	Necessary and sufficient conditions
		To say that A is necessary for B is to say that B cannot occur without A occurring, or that whenever (wherever, etc.) B occurs, so does A. We might say that being sixteen is necessary for having a driver's license.
		In either case, the important thing is to note that one thing is assumed (fire, a license), and a second thing is derived as "necessary following." Being sixteen is the necessary condition in the first case; smoke is the necessary condition in the second (though, again, we ordinarily would not call it a "condition").
		If A is a necessary condition for B, then the logical relation between them is expressed as "If B then A" or "B only if A" or "B → A".
	www.fact-index.com /n/ne/necessary_and_sufficient_conditions.html (685 words)

	Sophia on the web: Informal Logic Page ~ Necessary and Sufficient Conditions
		It is not uncommon for people to assume that an event will simply occur simply because the necessary condition is present; however such thinking mistakes a necessary condition for a sufficient one.
		Yes responses show that it could be necessary or sufficient (12), but another check is necessary.
		Since it is yes, then it is a necessary condition.
	members.aol.com /moresophia/condition.html (416 words)

	CmSc180 Conditional statements
		The sufficient condition for n to be divisible by 2 is to be divisible by 6.
		The necessary condition for n to be divisible by 6 is to be divisible by 2
		The necessary condition for n to be odd is to be an integer.
	www.simpson.edu /~sinapova/cmsc180/cmsc180-04/WebLN180/L05-SuffN.htm (836 words)

	DOE Closure Process for Necessary and Sufficient Sets of Standards (54 out of 99)
		Depending on the complexity or controversy surrounding a particular situation, the Convened Group responsible for planning and conducting a particular necessary and sufficient process may decide that confirmation by an independent team is needed to support approval of the set.
		Tailoring a necessary and sufficient set of standards to the work and hazards ensures that the desired level of protection is achieved efficiently.
		(9) Document: (a) the necessary and sufficient set of standards, (b) the justification for the set, (c) implementation assumptions and interfaces, and (d) a justification to support an exemption from regulatory requirements that are judged by the team not to add value to the achievement of adequate protection.
	www.ornl.gov /adm/camext/EshPlan/Plan99/w3vdkhgw.html (4368 words)

	Necessary vs. Sufficient Conditions (Site not responding. Last check: 2007-10-20)
		Definition: A necessary condition for some state of affairs S is a condition that must be satisfied in order for S to obtain.
		Being human is a sufficient condition for being a mammal.
		This means that being a male sibling is both necessary and sufficient for something to be a brother.
	philosophy.wisc.edu /hausman/104/nec-suf.htm (388 words)

	Sufficient and Necessary Statistics, W van der Linden (Site not responding. Last check: 2007-10-20)
		The property of sufficiency becomes interesting only if we are able to reduce the number of response vectors, combining them into a statistic without losing any information about the parameters.
		Dynkin's terminology has not become popular; it has been beaten by the more familiar concept of a "minimal sufficient" statistic, which is precisely a statistic that is both sufficient and necessary.
		Necessary and sufficient statistics for a family of probability distributions.
	www.rasch.org /rmt/rmt63d.htm (431 words)

	Obiter Dicta: Critical Thinking: Necessary and Sufficient Conditions
		To say that the satisfaction of A is necessary for the satisfaction of B is to say that B cannot obtain unless A obtains as well.
		So, in this case, a necessary condition for being able to vote is being at least eighteen years old.
		To say that the satisfaction of A is sufficient for the satisfaction of B is to say that as long as A obtains, B obtains.
	orda.blogspot.com /2005/03/critical-thinking-necessary-and.html (354 words)

	THE NECESSARY AND SUFFICIENT CONDITIONS FOR A
		This paper defines an efficient model as the one that satisfies the necessary and sufficient conditions.
		One should think of the necessary condition as asking the question “Within the candidate forecasting model, are all parameter estimates required?” This question is implicitly answered by determining whether parameter estimates are statistically significantly different from zero.
		In such cases, more than one sufficient variable may need to be added to the model to satisfy the sufficiency requirement.
	www.autobox.com /conditions2.html (2993 words)

	Necessary and Sufficient Conditions (Site not responding. Last check: 2007-10-20)
		The truth of 'p' is a sufficient condition for the truth of 'q'.
		Finishing her paper is a necessary and sufficient condition for Mary's coming to the party.
		Sufficient: If you do satisfy all the academic requirements and pay all your bills and fines, then you are eligible to graduate.
	www-unix.oit.umass.edu /~phil100b/necsuffcond.html (572 words)

	Sophia on the web: Informal Logic Page ~ Necessary and Sufficient Conditions
		Yellowness is a ________________ condition for being a banana.
		A banana is a _____________ condition for yellowness.
		Being a flower is a _______________ condition for being a rose.
	members.aol.com /moresophia/condition_answers.html (321 words)

	Necessary and Sufficient Conditions
		A is necessary for B iff (“if and only if”) B can’t occur without A. Whenever you have B, you have A. Anything B is A. A is sufficient for B iff A guarantees B. Whenever you have A, you have B. Anything A is B. Examples:
		Being equilateral Being a square A is necessary for B. Being a rectangle Being a square A is necessary for B. Being an equilateral rectangle Being a square A is both necessary and
		In other words, Plato presupposes that all concepts are what Wittgenstein calls closed: i.e., Plato believes it is possible to specify the necessary and sufficient conditions for membership in the class of things denoted by any concept.
	instruct.westvalley.edu /lafave/nec+suff.htm (341 words)

	Necessary and Sufficient
		But, in any event, some things seem to be more sufficient than others.
		(A discussion on what mathematics may be sufficient for, could have fit right in with Fawcett's geometry course.) We just saw how the critical thinking skills helped study mathematics.
		Flener too ties the success of the course to the fact that students who took the course were the University School veterans of three years and were used to open ended investigations.
	www.maa.org /editorial/knot/NecessaryAndSufficient.html (1906 words)

	Necessary But Not Sufficient (Site not responding. Last check: 2007-10-20)
		Technology is necessary, but not sufficient is the core theme of this book.
		Towards the end of Necessary But Not Sufficient you will find you want to go back and re-read The Goal, and Its Not Luck so you can better understand the TOC applications.
		Technology is merely a tool, often necessary, but not sufficient in and of itself.
	www.pcprotection.ca /books-reviewed/0884271706.html (2639 words)

	ADHD Evaluation: What Is Necessary and Sufficient? (Site not responding. Last check: 2007-10-20)
		For many of these children their inattentiveness is not the result of a biologically based problem with developing self-control.
		At the other extreme, it is also not necessary to administer a ten hour neuropsychological battery to a child referred for symptoms of ADHD in which a brief history and general questionnaires reveal no indications of delayed academic achievement or performance, severe emotional problems or family adversity.
		When parents suspect their children may experience problems as a result of ADHD, a good place to begin is by obtaining a book or video about the subject and becoming educated about common signs, symptoms and behaviors as well as co-occurring problems.
	www.addresources.org /article_necessary_diagnosis_goldstein.php (992 words)

	The Concept of Necessary Conditions and Sufficient Conditions
		it is sufficient for) an object's having four sides that it is a square.
		While having four sides is a necessary condition for something's being a square, that single condition is not, by itself, sufficient (to guarantee) something's being a square, i.e.
		Thomas White, the author of a recent textbook in philosophy, attempted to use as his example the specifying of the necessary and sufficient conditions for hearing music from a Walkman®.
	www.sfu.ca /philosophy/swartz/conditions1.htm (2120 words)

	Necessary and Sufficient Conditions for Optimal Offers in Electricity Markets
		Necessary and Sufficient Conditions for Optimal Offers in Electricity Markets: SIAM Journal on Control and Optimization Vol.
		82--100] recently discussed necessary conditions for an optimal offer curve when there is uncertainty in the demand and in the behavior of other participants in the market.
		Finally, we establish sufficient conditions for an offer curve to be locally optimal.
	epubs.siam.org /sam-bin/dbq/article/36780 (214 words)

	Necessary vs. Sufficient Conditions: Self-Test Answers (Site not responding. Last check: 2007-10-20)
		The truth of P is sufficient for, guarantees the truth of Q. If it is true that if P then Q, then Q is a necessary condition for P. True.
		In general if it is the case that P is true if and only if Q is true, then Q is necessary and sufficient for P and P is necessary and sufficient for Q. If anything fails to be male or fails to be a sibling, then it is not a brother.
		So being a male sibling is a sufficient condition for being a brother.
	philosophy.wisc.edu /hausman/341/Skill/nec-suf-answers.htm (461 words)

	On Strongest Necessary and Weakest Sufficient (ResearchIndex) (Site not responding. Last check: 2007-10-20)
		Abstract: Given a propositional theory T and a proposition q, a sufficient condition of q is one that will make q true under T, and a necessary condition of q is one that has to be true for q to be true under T.
		In this paper, we propose a notion of strongest necessary and weakest sufficient conditions.
		Intuitively, the strongest necessary condition of a proposition is the most general consequence that we can deduce from the proposition under the given theory, and the weakest sufficient condition...
	citeseer.ist.psu.edu /650882.html (406 words)

	Necessary and sufficient (Site not responding. Last check: 2007-10-20)
		A necessary cause represents a condition that must be present for the effect to follow
		A sufficient cause represents a condition that will pretty much guarantee the effect
		In social science, evidence of either a necessary or sufficient cause is often used as the basis for concluding that a relationship is causal
	www.unc.edu /courses/pre2000fall/soci051/tsld044.htm (52 words)

	Necessary and Sufficient Conditions
		This is good, but we need something more specific, since it is also a necessary condition for "being a boat" that you have an engine.
		A sufficient condition for X is a property that -- once we know it is present -- we know with certainty that an X is present.
		Notice that "having three enclosed interior angles 90, 60, and 30" is not a necessary condition for "being a triangle" (there are right triangles, isoceles triangles, etc), but it is a sufficient condition for "being a triangle".
	www2.drury.edu /cpanza/introreview1-1.html.html (671 words)

	Philosophical Dictionary: Nagel-Newton
		Necessary truth is a feature of any statement that it would be contradictory to deny.
		In logic, one proposition is a necessary condition of another when the second cannot be true while the first is false, and one proposition is a sufficient condition for another when the first cannot be true while the second is false.
		Thus, for example: the presence of oxygen is a necessary condition for combustion, and the flow of electrical current is a sufficient condition for the induction of a magnetic field.
	www.philosophypages.com /dy/n.htm (1220 words)

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