英文字典中文字典


英文字典中文字典51ZiDian.com



中文字典辞典   英文字典 a   b   c   d   e   f   g   h   i   j   k   l   m   n   o   p   q   r   s   t   u   v   w   x   y   z       







请输入英文单字，中文词皆可：

decidability    
可决定性; 可判定性

可决定性; 可判定性

decidability
半可决策性

A property of sets for which one can determine
whether something is a member or not in a {finite} number of
computational steps.

Decidability is an important concept in {computability
theory}. A set (e.g. "all numbers with a 5 in them") is said
to be "decidable" if I can write a program (usually for a
{Turing Machine}) to determine whether a number is in the set
and the program will always terminate with an answer YES or NO
after a finite number of steps.

Most sets you can describe easily are decidable, but there are
infinitely many sets so most sets are undecidable, assuming
any finite limit on the size (number of instructions or number
of states) of our programs. I.e. how ever big you allow your
program to be there will always be sets which need a bigger
program to decide membership.

One example of an undecidable set comes from the {halting
problem}. It turns out that you can encode every program as a
number: encode every symbol in the program as a number (001,
002, ...) and then string all the symbol codes together. Then
you can create an undecidable set by defining it as the set of
all numbers that represent a program that terminates in a
finite number of steps.

A set can also be "semi-decidable" - there is an {algorithm}
that is guaranteed to return YES if the number is in the set,
but if the number is not in the set, it may either return NO
or run for ever.

The {halting problem}'s set described above is semi-decidable.
You decode the given number and run the resulting program. If
it terminates the answer is YES. If it never terminates, then
neither will the decision algorithm.

(1995-01-13)


请选择你想看的字典辞典：
单词字典翻译
Decidability查看　Decidability　在百度字典中的解释百度英翻中〔查看〕
Decidability查看　Decidability　在Google字典中的解释Google英翻中〔查看〕
Decidability查看　Decidability　在Yahoo字典中的解释Yahoo英翻中〔查看〕

安装中文字典英文字典查询工具!


中文字典英文字典工具:
选择颜色:
输入中英文单字

































































英文字典中文字典相关资料:


  • On demand apps not working - Virgin Media Community - 5669402
    If we try to connect, the screen goes black and none of the remote buttons work The only solution is to reboot the box, but that only gets the box working again - we still can't get the on-demand apps Other on-demand channels, such as C5 and U, work without problem, as do Netflix and Amazon Prime Any suggestions? Robin Withey
  • Router issues - Virgin Media Community - 5551054
    My router randomly turns off and on Can you help please nbsp; - 5551054
  • Install Connection Query - Virgin Media Community - 5479915
    There is the one with the connector that seems to have been fitted today The top left one is the end of the cable that feeds down under the drive and back up into the house The one circled at the bottom is the existing wire that feeds under the drive to the Nynew Toby on the pavement (I thought they would be connecting the two existing wires together but they’ve added a new one) Hope
  • Sign In - Virgin Media Community
    Keep me signed inWe'll keep you signed in on this device We will only ask for your password when updating sensitive account information For security reasons, don't select this option on a public device
  • Hi, any news on when you will go live in Upton Chester?
    The street works and the pole have been done in our road in Upton, Chester, just wondering when we will be able to get connected please? - 5499938
  • Overheated box - Virgin Media Community - 5439215
    I get a message come up saying my virgin box is overheated whilst I’m watching Disney+, and then it switches off This is a new box I have had for 4 days - 5439215
  • Exterior (phone) cable detached and loose - Virgin Media Community
    Hi gpowell99 Welcome back to the community forums Sorry to hear of your concerns with a loose cable outside your home Does the cable come from our omni box which is the box attached to the external wall of your home, or does this come directly from the telephone pole? Are you able to post an image and we can look into seeing if this cable is ours so that we have the rights and ability to work
  • Over heating TV box - Virgin Media Community - 5596095
    If your box is over heating first thing to check is the ventilation below the box, if it's over heating and making a noise you would guess that it's a faulty fan Is the box switching off due to the over heating, you might need to leave it turned off You need to call Virgin on 150 from a Virgin phone, mobile or landline, or 0345 454 1111 from any other phone to report a fault, or wait here





中文字典-英文字典  2005-2009