« first day (207 days earlier)      last day (2276 days later) » 

user21820
user21820
05:38
← 1 message moved from Logic
@taritgoswami Hi!
What did you try?
 
8 hours later…
tarit goswami
tarit goswami
14:06
@user21820 Actually I don't know how to formally prove this kind of statement(I think it belongs to Mathematical Logic)
user21820
user21820
@taritgoswami No it does not really belong to mathematical logic. If you read the topics listed in the description of the Logic chat-room, you would find that it is mainly for the mathematical study of logic. Questions like yours belong to learning how to use basic logic, not (yet) study it.
The first step is to convert the phrases you are interested in into logical form. Show me how to translate those sentences, and we will go from there.
tarit goswami
tarit goswami
(I try) $\land$ (I have talent) $\implies$ I can be a mathematician
Like this?
@user21820 and for (2), (I become a mathematician) $\implies$ I will be happy
user21820
user21820
@taritgoswami Good!
You don't have to use LaTeX here, just use English words. Also, when translating we always replace the individual pieces by propositional variables. You know how to do that, right?
For example, if "I try" is "A" and "I have talent" is "B" and "I can be a Mathematician" is "C", then the first is "A and B implies C".
I presume you know the precedence rules, that "and" has higher precedence than "implies"?
tarit goswami
tarit goswami
@user21820 No I don't :p
Can you tell me?
user21820
user21820
Oh okay. Conventionally we use this precedence order (highest to lowest): not, and, or, implies/iff.
The last two people don't usually assume their precedence order, so we need brackets to make it clear.
So according to the precedence rules, "A and B implies C" is read as "( A and B ) implies C".
tarit goswami
tarit goswami
14:23
Ok, but if and has higher presedence then why we need braket?
automatically the operation and will be performed first, right?
@user21820 I mean this sentence is not clear :(
user21820
user21820
@taritgoswami Sorry I meant to say that people usually do not depend on precedence rules for "implies" and "iff".
tarit goswami
tarit goswami
OK
user21820
user21820
They come after all the rest, but you should use brackets to make your intended meaning clear if you have consecutive "implies" or "iff".
And there is good reason for that, since "( A implies B ) implies C" is not equivalent to "A implies ( B implies C )".
So back to your question, what is your definition of "valid"?
tarit goswami
tarit goswami
Validity check means I need to check if the conclusion from previous two statement is True or not
right?
user21820
user21820
No?
What were you taught?
tarit goswami
tarit goswami
14:34
@user21820 I will be taught Logic next semester.. haven't taught yet
Can we talk later? I have exam Monday :p
user21820
user21820
Okay sure. Just drop in here another day.
tarit goswami
tarit goswami
OK, good night, bye for now
user21820
user21820
See you!
Theantomc
Theantomc
15:25
Hi guys :)

« first day (207 days earlier)      last day (2276 days later) »