Existential Validities and Related Enigmas

Authors

  • Paulo A. S. Veloso UFRJ
  • Luiz Carlos Pereira UFRJ
  • Edward H. Haeusler PUC-RJ

DOI:

https://doi.org/10.5380/dp.v6i2.17336

Keywords:

Lógica, quantificação, validades existenciais, validades universais, tautologias, Logic, quantification, existential validities, universal validities, tautologies

Abstract

Logic does not have purely existential theorems: the only existentialsentences that are valid are those with valid universal analogues. Here, we showindeed this is so, when properly interpreted: every existential validity has asimple universal analogue, which is also valid. We also characterize existentialand universal validities in terms of tautologies.

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How to Cite

Veloso, P. A. S., Pereira, L. C., & Haeusler, E. H. (2009). Existential Validities and Related Enigmas. DoisPontos, 6(2). https://doi.org/10.5380/dp.v6i2.17336

Issue

Vol. 6 No. 2 (2009): Grammar, Truth and Inference

Section

Articles

License

Copyright for articles published in this journal belongs to the author, with first publication rights for the journal. Because of appearing in this public access journal, the articles are free to use, with terms of reference, in educational and non-commercial applications.