Could someone somewhat plainly explain what is unification, when it is

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Discussion Overview

The discussion centers around the concept of unification, specifically in the context of mathematical logic and its applications in computer science. Participants explore the definition, examples, and implications of unification, contrasting it with its use in physics.

Discussion Character

  • Conceptual clarification
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant requests a plain explanation of unification, its usage, and its benefits.
  • Another participant notes that unification generally means combining two concepts, highlighting the famous example of unifying gravity and electromagnetism in physics.
  • A participant clarifies that they are specifically referring to unification in mathematical logic related to computer science.
  • A definition from Wikipedia is provided, explaining unification as a join with respect to a specialization order, where a term is a substitution instance of both terms involved.
  • One participant offers an intuitive example, stating that 'red' and 'ball' can be unified as 'red ball', while 'square' and 'circle' cannot be unified.
  • Another participant attempts to clarify the concept by discussing unification as a chain of inclusion, using 'labrador', 'dog', and 'animal' as examples, but expresses uncertainty about their explanation.
  • A later reply confirms that the unification of 'labrador' and 'animal' is 'animal', and provides another example of 'labrador' and 'persian' unifying to 'mammal'.

Areas of Agreement / Disagreement

Participants express varying interpretations of unification, with some uncertainty about the definitions and examples provided. No consensus is reached on a singular definition or understanding of unification.

Contextual Notes

Participants' explanations rely on different interpretations of unification, and there are unresolved aspects regarding the precise definitions and examples of minimal unification.

EvLer
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Could someone somewhat plainly explain what is unification, when it is used and what does it "buy"? I just have heard of it and searched online a bit but it is a bit hazy for me.
A small example would be appreciated as well :redface: .
 
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What field are you talking about? "Unification", in general, means "unifying" or combining two concepts. The most famous "unification" is not in mathematics but in physics: unifying Gravity and Electromagnatism, the "unified field theory".
 
sorry, yeah, I am talking about mathematical logic (computer science related) more so than physics.
 
From wikipedia:

In mathematical logic, in particular as applied to computer science, a unification of two terms is a join (in the lattice sense) with respect to a specialisation order. That is, we suppose a preorder on a set of terms, for which t* ≤ t means that t* is obtained from t by substituting some term(s) for one or more free variables in t. The unification u of s and t, if it exists, is a term that is a substitution instance of both s and t. If any common substitution instance of s and t is also an instance of u, u is called minimal unification.

I think one can think of it as a token that is of both types. There is no possible unification of 'square' and 'circle' because one can't get a square circle, but 'red' and 'ball' are unified in 'red ball'. Anyway, that's my intuition of it. 'Red ball' is a minimal unification because all other unifications (like 'red beach ball') do qualify as red balls.

Or perhaps I'm totally wrong.
 
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Oh, I didn't quite read it properly. A unification is a join between a general term and a more specific term, like a chain of inclusion. A labrador is a dog and a dog is an animal, so I guess the unification of labrador and animal is that chain (labrador <= dog <= animal). A minimal unification is the shortest chain of inclusion between the two terms.

Er, no, that's not right either. One of the mathematical folks will surely explain it shortly.
 
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Your first example was correct. The unification of "labrador" and "animal" is "animal". In a slightly more useful example, the unification of "labrador" and "persion", in terms of biology, would be "mammal", the smallest class that includes both.
 

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