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workshop_2 [2014/05/30 08:43] mellies |
workshop_2 [2014/05/30 08:45] (current) mellies |
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| //Polarities and classical constructiveness// | //Polarities and classical constructiveness// | ||
| - | > I will recall what constructive can mean in the context of classical logic, as accounted for by double negation translations and control operators in programming. | + | > I will recall what constructive can mean in the context of classical logic, as accounted for by double negation translations and control operators in programming. Girard proposed a few years back a classical sequent calculus where negation is strictly involutive (¬¬A = A) by taking formally into account the polarity of connectives. I will show that this idea is very natural from the point of view of control operators, leading us to a natural deduction where negation is involutive (¬¬A ≅ A). One of the main aspect is that we do not consider that composition needs to be associative when the middle map is from positives to negatives. In a second time I will therefore introduce duploids, which characterises this non-associative composition directly, and relate them to adjunctions. |
| - | Girard proposed a few years back a classical sequent calculus where negation is strictly involutive (¬¬A = A) by taking formally into account the polarity of connectives. I will show that this idea is very natural from the point of view of control operators, leading us to a natural deduction where negation is involutive (¬¬A ≅ A). | + | |
| - | One of the main aspect is that we do not consider that composition needs to be associative when the middle map is from positives to negatives. In a second time I will therefore introduce duploids, which characterises this non-associative composition directly, and relate them to adjunctions. | + | |
| **Palmgren**\\ | **Palmgren**\\ | ||