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+31 votes

The total number of prime implicants of the function $f(w, x, y, z) = \sum (0, 2, 4, 5, 6, 10)$ is __________

+47 votes

Best answer

+2

this is wrong u r saying about essential prime implecants and also EPI is 3 because where quad is formed that group must be countede as 1 so EPI is also 3

0

This is Essential Prime Implicants not Prime Implicants.

Prime Implicants is all possible combinations right? I'm getting 6

Prime Implicants is all possible combinations right? I'm getting 6

0

doesn't prime implicants mean the number of product terms that come in the minimized sum of products....

correct me if i am wrong

correct me if i am wrong

+14

No, Not necessary.

**Prime Implicant :** the biggest subcube that should not be completely covered by any other subcube (some may be covered)

Have a look my this answer. ( this can be of some help to you)

+2

then what is the difference between PI and EPI?

Here is what wiki says :

As per this definition PI may have all it's outputs covered, but EPI shouldn't

+1

@Shalini EPI are marked with * in the given answer. And question asks for no. of PI and I guess you are counting no. of distinct terms which can come in any PI.

0

Yes Sir. But I'm failing to understand the definition of PI. If a ques asks for num of PIs, then we should consider minimal covering of the map?(i.e. 1 subcube should not be completely covered by another subcubes, for all subcubes)

+3

+9 votes

(Can be solved using K-Map also. )

Place all minterms that evaluate to one in a minterm table.

**Input (first column for no. of 1's)**

0 | m0 | 0000 |

1 | m2
m4 |
0010
0100 |

2 | m5
m6 m10 |
0101
0110 1010 |

Combine minterms with other minterms. If two terms vary by only a single digit changing, that digit can be replaced with a dash indicating that the digit doesn't matter. Terms that can't be combined any more are marked with a "*". When going from Size 2 to Size 4, treat '-' as a third bit value. For instance, -110 and -100 or -11- can be combined, but -110 and 011- cannot. (Trick: Match up the '-' first.)

**First Comparison**

0 | (2, 0)
(4, 0) |
00-0
0-00 |

1 | (6, 2)
(10, 2) (5, 4) (6, 4) |
0-10
-010 010- 01-0 |

**Second Comparison**

0 | (6, 4, 2, 0) | 0--0 |

**Prime Implicants**

(6, 4, 2, 0) | 0--0 |

(10, 2)
(5, 4) |
-010
010- |

Answer: Total number of prime implicants

Source: Finding prime implicants - Quine-McCluskey algorithm - Wikipedia

+6 votes

+2 votes

I think this is bit easier to understand.

The hint here is that we try to find the minimum number of groups(octa(eight 1's) ,quad (four 1's),dual(two 1's) that can be formed and that represents the minimum number of implicants that covers F which is Prime Implicant.

Here, we can form 1 quad and 2 duets.3 prime implicants.

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