Maths question
 

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[Closed] Maths question

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Is there a name to describe a set of functions that when taken together cover all possible input and output values, but without overlapping?

Like for example, one function a(x) > 0 that applies to x > 0 and b(x) < 0 that applies to x < 0? A name for the both a and b together?

What I am working on is rules that say:

when A is known then set B to some function of A
when A is unknown then set B to unknown

I want to say that the two rules must constitute a complete set, but I wondered if there is a technical term for this?


 
Posted : 16/12/2018 11:53 pm
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Simultaneous equations?


 
Posted : 17/12/2018 12:34 am
 aP
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Boolean logic?


 
Posted : 17/12/2018 4:51 am
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In maths, I would call it a discrete function of x that covers the real space. Don't know if the following pic example will show.
discrete function

My parter who is an Engineer would call it a discrete switch.

Why do you need to know, as in who/what is this for?

(Also you need an x=0 to cover all of the real space and I don't think you mean a(x)>0 but a(x>0)? In which case define f(x) = {a(x), x>=0, b(x), x<0. Then define a and b on the next line. Clearer that way.).


 
Posted : 17/12/2018 7:02 am
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Should have also said, I presume you mean a(x>0) rather than a(x)>0. You can define f(x) in terms of a(x) and b(x) first. Then describe a and b.


 
Posted : 17/12/2018 7:11 am
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If the gap at x=0 was covered I'd have called it a continuous set of functions. But IANAM and they are very pedantic about definitions.


 
Posted : 17/12/2018 8:34 am
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Piecewise Function

http://mathworld.wolfram.com/PiecewiseFunction.html

but like above, you'll be wanting to specify 0 (either explicitly as a single point, or by making one of the other operators either <= or >=, or perhaps by formally excluding it as an input)


 
Posted : 17/12/2018 8:44 am
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I want the name for the whole complimentary set. I want to say these rules/functions together cover all eventualities without overlap. I thought there might be a mathematical term for it but maybe it's a logical or computery one.


 
Posted : 17/12/2018 10:07 am
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Yeah, in more of a computational / coding sense, it's just a case switch or logical switch that covers all possibilities in the input. No idea if there is a term for that in the software development community.


 
Posted : 17/12/2018 10:43 am
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I want the name for the whole complimentary set. I want to say these rules/functions together cover all eventualities without overlap. I thought there might be a mathematical term for it but maybe it’s a logical or computery one.

There is, Andy the Rocketeer told you?

Piecewisefunction


 
Posted : 17/12/2018 12:59 pm
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You need a collective noun, I suggest you use 'bobbins' and just bluff your way..

I present the bobbins of functions which define the problem space....


 
Posted : 17/12/2018 4:00 pm
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Piecewise is good - I'll go for piecewise continuous function.


 
Posted : 17/12/2018 8:16 pm

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