Sound and complete, Computer Engineering

Assignment Help:

Dictator Dim wants to replace counting, in particular, counting the population of his land. To keep an accurate population count, Dictator Dim has instructed his secretary to add one + symbol to a record each time a citizen is born, and one - symbol to the record whenever a citizen dies. This has been going on ever since his rule began.

Dictator Dim is not concerned so much with the actual total population of his lands, just with the net change in population since his rule began. He would be forever disgraced if the net population change were ever negative. Refusing to solve this problem by counting, Dictator Dim instructs his secretary to find a sound and complete logic for the subset of all records that would not disgrace him.
More formally, define the following truth concept WFF's = {+; -}, i.e., all strings composed of only plus and minus symbols.
A WFF x is true if every prefix of x contains at least as many + symbols as - symbols.

Find a logic for this truth concept by proving that it is sound and complete. Hint: it may help to define additional judgement form(s)


Related Discussions:- Sound and complete

What do you mean by first fit, What do you mean by first fit? First fi...

What do you mean by first fit? First fit allocates the first hole that is big enough. Searching can either begin at the beginning of the set of holes or where the last first-f

What is transformation, What is transformation? A transformation is a m...

What is transformation? A transformation is a mapping from the domain of models to the range of models. When modeling, it is significant not only to focus on customer needs, bu

Dbms, write er diagram for company database

write er diagram for company database

How does the computer execute a program, Let's attempt to answer a fundamen...

Let's attempt to answer a fundamental question: 'How does the Computer execute a Program?' Let's describe this with the help of an example from higher level language domain. Pr

How to export a dreamweaver document as xml file, Q. How to export a dreamw...

Q. How to export a dreamweaver document as xml file? Step 1: Choose File -> Open, Step 2: Select document which uses a template (and has editable regions) Step 3: Click O

Full adder, design a FULL adder with two half adders and an or gate

design a FULL adder with two half adders and an or gate

Explain what is a macro and why is it important, Question 1: Spreadshee...

Question 1: Spreadsheet packages are widely used in Business. a) Explain why spreadsheets are so useful. b) Spreadsheet files are sometimes saved for use by other software p

What is a spool request, What is a Spool request? Spool requests are f...

What is a Spool request? Spool requests are formed during dialog or background processing and placed in the spool database with information about the printer and print format.

Explain the difference between a subroutine and macro, Explain the differen...

Explain the difference between a subroutine & macro. It is inefficient to have to write code for standard routines.  For instance reading a character form the keyboard or savin

Blocking and non-blocking network, Blocking and Non-Blocking network In...

Blocking and Non-Blocking network In non-blocking networks the route from any free input node to any free output node can always be offered. Crossbar is an best example of non-

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd