Calling math wizards

[RadiclDreamer]

Its the name of the theory that all X's are letters but not all letters are X's. I know crappy description but I need to know what that is called

 

[Anubis]

the theroy of bunnies

 

[RadiclDreamer]

I remember in math it was a theory that all (blank) are (something) but not all (blank) are something.

Like all americans speak english (yeah right) but not all english speakers are american

 

[Drakkon]

you mean like the theory that all squares are rectangles but not all rectangles are squares?

 

[RadiclDreamer]

Originally posted by: Drakkon
you mean like the theory that all squares are rectangles but not all rectangles are squares?

Something like that yeah. What was it called.

 

[Injury]

logical expression(s)?

 

[zinfamous]

I thought that was more of a non-math logic thing than it was a math concept. More of an argumentation logic that has applications in mathematics.

 

[Drakkon]

its not really a theory - just called "subsets" - unless your looking for the name of the theory that proves subsets - which I don't think there is one (a name that is - theory is well documented)...

 

[Injury]

Originally posted by: zinfamous
I thought that was more of a non-math logic thing than it was a math concept. More of an argumentation logic that has applications in mathematics.

You're losing me.

 

[Paperdoc]

Is it ineritance? Since "X" is a letter, it is a subset of the set of all letters. And because of that, it inherits all the properties that characterize all letters. However, it has some of its own additional properties that do not characterize other letters, because those others are in different subsets.

 

[chuckywang]

Originally posted by: RadiclDreamer
Its the name of the theory that all X's are letters but not all letters are X's. I know crappy description but I need to know what that is called

That's not a theory. That's a part of predicate logic.

 

[DrPizza]

Are you looking for simple things in logic:
converse
inverse
contrapositive

Then there are lots of others...
modus ponens, modus tollens, hypothetical syllogism, disjunctive syllogism, constructive dilemma, destructive dilemma, etc.

Maybe searching for that stuff will help you accidentally run across the term you're looking for?

 

[BrownTown]

some sort of very basic set theory stuff?

 

[frostedflakes]

Yeah, sounds more like logic than something strictly math related. I know what you're talking about, but am having trouble putting a term to it. Does exclusivity ring a bell? For some reason, it sounds right.

 

[SpecialEd]

like others said, your working with logic:

All bunnies are animals, but not all animals are bunnies.

 

[JS80]

Preparing for LSATs?

 

[sao123]

set theory

 

[zinfamous]

Originally posted by: Injury

Originally posted by: zinfamous
I thought that was more of a non-math logic thing than it was a math concept. More of an argumentation logic that has applications in mathematics.

You're losing me.

meaning: it's logic--and not necessarily a math concept.

It's a logical argumentation concept that has application in mathematics.

 

[Injury]

Originally posted by: zinfamous

Originally posted by: Injury

Originally posted by: zinfamous
I thought that was more of a non-math logic thing than it was a math concept. More of an argumentation logic that has applications in mathematics.

You're losing me.

meaning: it's logic--and not necessarily a math concept.

It's a logical argumentation concept that has application in mathematics.

heh... I knew... I was just feigning stupid.

 

[QED]

Perhaps you are thinking of notion of commutativity? It's the notion that you can reverse the order or something (say, switching the two sides of an equation, or switching the object and the subject of a sentence) and end up with a completely equivalent result.

The first example (switching two sides of an equation) is generally commutative, since saying "a equals b" is amost always entirely equivalent to saying "b equals a". The second example (switching the object and the subject of a sentence) is generally non-commutative-- for instance, "John threw the ball" is not at all equivalent to saying "The ball threw John". However, if I choose a different verb, it could be commutative-- for instance, "John was near the ball" is equivalent to saying "The ball was near John"-- so you could say "being nearby" is commutative.


A membership relationship is also, generally speaking, non-commutative since, for instance, saying "All X's are letters" is not at all equivalent to saying "All letters are X's".

 

[Chaotic42]

Are you talking about Venn Diagrams?

 

[RapidSnail]

Originally posted by: Injury

Originally posted by: zinfamous

Originally posted by: Injury

Originally posted by: zinfamous
I thought that was more of a non-math logic thing than it was a math concept. More of an argumentation logic that has applications in mathematics.

You're losing me.

meaning: it's logic--and not necessarily a math concept.

It's a logical argumentation concept that has application in mathematics.

heh... I knew... I was just feigning stupid.

Damn, you're good.

 

[nineball9]

Are you thinking of the fallacy of affirming the consequence?