Recent content by antonio85

  1. A

    Graduate A formula provable without is a tautology

    How can I prove that: If a formula A is provable without use of substitution axioms, nonlogical axioms, equality and identity axioms, and the \exists-introduction rule, than A is a tautology. I try to act this way: consider a tautology A and show that using propositional axioms I get...
  2. A

    Graduate Complex numbers and hamilton quaternions generate [tex]M_{2}(C)[/tex]

    How can M_{2}(\mathbb{C}) be written as a combination of elements of \mathbb{C} and elements of \mathbb{H}?
  3. A

    Graduate Isomorphism of Hom_K(V,K) and Hom_K(V⊗V,K)

    Why these two tensor products are isomorphic? Hom_{K}(V,K) \otimes Hom_{K}(V,K) and Hom_{K}(V \otimes V,K) where K is a field and V is a vector space over K.
  4. A

    Graduate Quadratic forms with p-adic coefficient

    How can I found out in which p-adic fields a quadratic form represent 0? For example in which p-adic fields does the form 3x2+7y2-15z2 represent zero?