← 7 messages moved from Basic Mathematics

@PaxDaga: I am glad to teach all who want to learn from me. To make it a pleasant experience, and maintain a conducive environment in the basic mathematics chat-room, please do not post off-topic remarks there. Regarding attempted solutions to the exercises, please post them neatly in that chat-room. This includes:

By "allow" here I simply mean that if your attempt does not satisfy what I "allow" then I do not consider it a correct solution no matter how 'close' it is to a correct solution.

@PaxDaga In your last few messages you did not follow my instructions (1) and (2).

i will follow it from now is that the misatke ? @user21820

Unless you follow my instructions, I cannot tell whether you understand the solution at all.

which solution

?

I have to go. Bye.

[P6]

If neg(A or B):
  If A:
    A or B
    neg(A or B)
    contradiction
  neg A
  If B:

    A or B
    neg(A or B)
    contradiction
  neg B
  neg A and neg B

LEM proof

If neg(B or neg B):
  neg B and neg(neg B)
  neg B and B
  contradiciton

B or neg B

The demorgan lwas taht i used is in p4

now i think its a complete proof

If neg(A or B):
  If A:
    A or B
    Contradiction
 neg A
 If B:
  A or B
  Contradiction
 neg B
 neg B and neg A

@user21820 is it correct

@user21820 is this format ok

@PaxDaga No, this format is not ok.

> (2) Each attempt should be a single complete proof to the stated exercise (unless I allow you to split it into parts).

[P4]

If neg A and neg B:
  If A or B:
    If A:
      A or B
      Neg(A or B)
      Contradiction
    If B:
      A or B
      Neg(A or B)
      Contradiction
    A implies contradiction
    B implies contradiction
    A or B implies contradiction
    A or B
    Contradiction
  neg(A or B)
neg A and neg B implies neg(A or B)
If neg(A or B):
  If A:
    A or B
    Contradiction
  Neg A
  If B:
    A or B
    Contradiction
  neg B
  neg A and neg B
neg(A or B) implies neg A and neg B
negA and neg B double implies neg(A or B)

@user21820 full p4]

[Excluded Middle (proving it so i can use it in p6 will use p4)]
If neg(A or neg A):
  neg A and neg(neg A) [P4]
  neg A and A
  contradiction
A or neg A

@user21820 please check both

@PaxDaga Wrong. You did not check each line against the deductive rules.

By the way, it is common to use "not" instead of "neg" for "¬". And use "equiv" or "iff" for "⇔".

@PaxDaga Wrong also. Again, you did not check each line against the deductive rules.

Is it wrong beacuse i skipped stpes

@user21820

Label every single line with the rule that allows you to write it, and make sure you are following the rule and not just writing whatever you want.

so iam skipping stpes or not?

or did i write a wrong line

@user21820

Do you want to follow my instructions?

i will but i want to know if i wrote a wrong line then atleast i know that i did not make a mistake i know the ruels for every line a will write it @user21820

*and

i guess you want to know how from neg(neg A) i got A

is that correct?

If neg A and neg B:
  If A or B:
    If A:
      A
      Neg A
      Contradiction
    If B:
      B
      neg B
      Contradiction
    A implies contradiction
    B implies contradiction
    A or B implies contradiction
    A or B
    Contradiction
  neg(A or B)
neg A and neg B implies neg(A or B)
If neg(A or B):
  If A:
    A or B
    Contradiction
  Neg A
  If B:
    A or B
    Contradiction
  neg B
  neg A and neg B
neg(A or B) implies neg A and neg B
negA and neg B double implies neg(A or B)

@user21820 please see now for LEM is that what you want me to do?

I made a silly mistake

@user21820 is it fine

@user21820 do you still want me to label for p4 now that if ound my mistake?

@PaxDaga Still wrong. Please note that I've no time to keep checking your attempts if you do not want to follow my instructions.

Also, please tell me whether you are fine with me moving your wrong attempts to your room.

@user21820 you can remove it

[P4]

If neg A and neg B:
  If A or B:
    If A:
      A [restate]
      Neg A [restate]
      Contradiction
    If B:
      B [restate]
      neg B [restate]
      Contradiction
      B implies contradiction
    A or B implies contradiction [or elim]
    A or B
    Contradiction [implies elim]
  neg(A or B)
neg A and neg B implies neg(A or B)
If neg(A or B):
  If A:
    A or B [or intro]
    Contradiction
  Neg A
  If B:
    A or B [or intro]
    Contradiction
  neg B
  neg A and neg B
neg(A or B) implies neg A and neg B

now i labbelled all then non trivial steps please tell me my mistake

can you at least tell me if the mistake is on the first part or the second?

@user21820

← 31 messages moved from Basic Mathematics

@PaxDaga I said:

> every single line

Whenever I say something, I mean exactly what I say.