Edit detail for SandBoxPolynomialQuizExplained revision 1 of 1

Coming Soon! (Or you can provide them!) Please insert comments after each problem. Original quizzes on SandBoxPolynomials#quizzes

(1) -> )clear all

   All user variables and function definitions have been cleared.

)set mess bot on

   Your user access level is compiler and this set option is therefore 
      not available. See the )set userlevel command for more 
      information.
variables (2*x+1/x)$DMP([x], EXPR INT)

(1)

---

)set mess bot on

   Your user access level is compiler and this set option is therefore 
      not available. See the )set userlevel command for more 
      information.
variables (2*y+1/y)$DMP([y], INT)

   There are 4 exposed and 7 unexposed library operations named 
      variables having 1 argument(s) but none was determined to be 
      applicable. Use HyperDoc Browse, or issue
                            )display op variables
      to learn more about the available operations. Perhaps 
      package-calling the operation or using coercions on the arguments
      will allow you to apply the operation.

   Cannot find a definition or applicable library operation named 
      variables with argument type(s) 
                        Fraction(Polynomial(Integer))

      Perhaps you should use "@" to indicate the required return type, 
      or "$" to specify which version of the function you need.

---

)set mess bot on

   Your user access level is compiler and this set option is therefore 
      not available. See the )set userlevel command for more 
      information.
a:=(2*x+1/x)$DMP([x], EXPR INT); variables a

(2)

---

)set mess bot on

   Your user access level is compiler and this set option is therefore 
      not available. See the )set userlevel command for more 
      information.
b:=(2*y+1/y)$DMP([y], INT); variables b

   There are 13 exposed and 11 unexposed library operations named + 
      having 2 argument(s) but none was determined to be applicable. 
      Use HyperDoc Browse, or issue
                                )display op +
      to learn more about the available operations. Perhaps 
      package-calling the operation or using coercions on the arguments
      will allow you to apply the operation.

   Cannot find a definition or applicable library operation named + 
      with argument type(s) 
               DistributedMultivariatePolynomial([y],Integer)
          Fraction(DistributedMultivariatePolynomial([y],Integer))

      Perhaps you should use "@" to indicate the required return type, 
      or "$" to specify which version of the function you need.

---

)set mess bot on

   Your user access level is compiler and this set option is therefore 
      not available. See the )set userlevel command for more 
      information.
x:DMP([x], EXPR INT):=x; variables (2*x+1/x)

(3)

---

)set mess bot on

   Your user access level is compiler and this set option is therefore 
      not available. See the )set userlevel command for more 
      information.
y:DMP([y], INT):=y; variables (2*y+1/y)

(4)

)set mess bot off

no cheating (1) variables (2*x+1/x)$DMP([x]?, EXPR INT)

(Got you, right? It got me too.

Yes. It took me a minute to realize that the interpreter parses this as:

(variables$DMP([x]?, EXPR INT))(2*x+1/x)

To understand this, repeat with )set mess bot on. You must understand what the Interpreter was doing before starting quiz (2))

Ok, that was pretty easy. :)

)set mess bot off (2) variables (2*y+1/y)$DMP([y]?, INT)

(Got me again! Repeat with )set mess bot on, read carefully, and compare with that from (1)).

This one is obvious. The only operation '/ in this domain is ?/? : (%,Integer) -> %' and y is not an Integer.

)set mess bot off (3) a:=(2*x + 1/x)$DMP([x]?, EXPR INT); variables a

Obvious result: [x]? What is hard about that?

)set mess bot off (4) b:=(2*y+1/y)$DMP([y]?, INT); variables b

Same error as in (2). But b is interpreted as a Variable which can be coerced to EXPR INT so result is [b]?

)set mess bot off (5) x:DMP([x]?, EXPR INT); variables (2*x+1/x)

Obvious. Result: [x]?. Essentially the same as (3)

)set mess bot off (6) y:DMP([y]?, INT); variables (2*y+1/y)

I wrote: "Error same as in (2)". So I have to admit I got this one wrong but I should not have. The explanation is simple. This is not a package call as it was in (2), so the interpreter is free to apply the usual coercion to 'FRAC DMP([y]?, INT) in order to obtain a selection for /'.

My apologies for putting up the wrong questions in Quizzes (5) and(6). The correct problems were given correctly on the Wiki pages but not in the email. In (5) x should have been assigned the value x (not just declared to be in DMP. Same for (6), where y should have been assigned the value y. In the version with the omissions, the first lines have no effect on the second lines.

William