This work concerns the cardinality and the
intersections of the P-problems, the NP problems
and the NP-Hard problems which are presented in
many works dealing with the notions of informatics
and logic [2,3,4]. However, we will focus in this
article on problems complexity by using the
ordinary notions available when we deal with
ordinary computers and not with nondeterministic
Turing machines (NTM) [5,6,7] or Quantum
Computers like it is explained in many works
[8,9,10].
Most of the results of this work are made by
considering that all NP-Hard problems that are not
NP-Complete problems have higher complexity
than NP-Complete problems and by considering that
all NP-Complete problems have one same
complexity that is directly linked to the value of a
number M that should exist and which is a fixed
number of P-Problems. We also supposed the
existence of a number of inputs that keeps all the P-
Problems with finite times of execution but makes
all NP-Hard problems with infinite times of
execution.
2 The considered modelling
Let's consider that each decidable problem can be
modelled by an algorithm that allows us to give an
estimation of the execution time of that algorithm.
The execution time of the algorithms of P problems
is finite. However, the execution times of NP-Hard
problems and NP-Complete problems are
considered infinite since these problems have never
been completely solved.
The set of P-problems is composed of elements
with and i>which are simple
problems that have a finite time of execution.
All the set of decidable problems respects a law
where And is a product that makes the sum
of the complexities of the problems of this product.
Consequently =pmeans that the execution
of the algorithm of the problem is equivalent to
the execution of the algorithm of the problem
followed by the execution of the algorithm of the
problem . Since the execution time of the
algorithm of the problem is finite, then is also
an element of the set of P-problems. Consequently,
an element of the set of P-problems can be a product
of n elements with n is a finite natural number.
Let's consider that there is an element e of the set of
P problems that has a null time of execution.
And thus:
=pe=p. (1)
And we don't care in this work about the presence of
a memory in the used computer. Hence, our
computer can repeat executing the same element
even if it is a solved problem.
And thus, we consider that we have:
=p
(2)
Hence, we consider that is in the set of P
problems for any element and for any strictly
positive natural number n since the problem
consists only on repeating the execution of the
same problem n finite times. Hence, our
computer shouldn't consider that is an infinite
loop when n is bigger than a defined value O that
depends on the computer system otherwise
becomes an undecidable problem.
We consider also that G is a fixed number of inputs
for all the decidable problems concerned by this
work. We know that the difference of complexity
time between P-problems and NP-Hard problems
increases as G becomes bigger. And thus, we
suppose the existence of a fixed number of inputs G
that keeps any P-problem as a product of a finite
number of elements which means that P-problems
will keep their finite times of execution, but we
consider that G is big enough to make all decidable
NP-Hard problems a product of an infinite number
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DOI: 10.37394/23205.2023.22.19