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The use of classical logic for some combinatorial proofs, as it is the case with Ramsey's theorem, can be localized in the Infinite Pigeonhole (IPH) principle, stating that any infinite sequence which is finitely colored has an infinite monochromatic subsequence. Since in general there is no computable functional producing such an infinite subsequence, we(More)
A 73-year-old patient (with arterial hypertension, aortic biological prosthetic valve, and atrial fibrillation as car-diovascular risk factors) presented with acute left-sided hemiplegia, hemianesthesia, and homonymous hemianop-sia. Brain magnetic resonance imaging (MRI) revealed restricted diffusion (Fig. 1) in two areas corresponding to the watershed(More)
We consider proofs in minimal logic, written in natural deduction style. The only rules are introduction and elimination for implication and the universal quantifier. The logical connectives ∃, ∧ are seen as special cases of inductively defined predicates, and hence are defined by the introduction and elimination schemes ∀ x (A → ∃ x A), Disjunction can be(More)
A 52-year-old man presented with progressive fatigue, drowsiness, weight loss, and memory impairment associated with left-sided temporal lobe seizures. Brain MRI revealed increased bilateral FLAIR signal in the hippo-campus, amygdala, mammillary bodies, hypothalamus and fornix (Figs. 1, 2). Blood analysis showed normal CRP, TSH, vitamin B1 and B12 levels.(More)
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