I think that you should go a little bit more into the detail of what you mean by necessary.
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From Wikipedia:**
Necessary may refer to:
Something that is a required condition for something else to be the case, see necessary and sufficient condition.
A necessary truth, something that cannot fail to be true, see logical possibility.
An important task or essential thing to do at a particular time or by a particular moment.
Necessity in the context of criminal law
An action somebody may feel they must do
In some languages a “necessary” is a bathroom or toilet. In English this is an archaic usage.
An economic need enunciated by US President Franklin D. Roosevelt in his 1944 Second Bill of Rights
A necessity in contract law