Subscribe: Logic Journal of IGPL - Advance Access
Preview: Logic Journal of IGPL - Advance Access

Logic Journal of the IGPL Advance Access

Published: Mon, 13 Nov 2017 00:00:00 GMT

Last Build Date: Mon, 13 Nov 2017 06:49:05 GMT


Proof systems for BAT consequence relations


An ongoing debate about the differences between formal provability in an axiomatic system and informal provability of mathematical claims in mathematics as a whole resulted in the construction of various logics whose main purpose is to capture the inferential behaviour of the notion of informal provability, just as multiple logics of formal provability capture the behaviour of the concept of formal provability. Known logics of informal provability, based on classical logic, are unable to incorporate all intuitive principles of informal provability (most notably, reflection, which says that whatever is provable is true). One solution to this problem is to treat informal provability as an operator (Shapiro, 1985, North Holland; Reinhardt, 1986, J. Philos. Log., 15, 427–74; Koellner, 2016, Oxford University Press). Another solution is to weaken some of the intuitively adequate principles (Horsten, 2002, Hansel-Hohenhausen). Recently, in yet another approach to the issue, two three-valued non-deterministic logics of informal provability have been developed (Pawlowski and R. Urbaniak, 2016, Rev. Symbo. Log.) to overcome this difficulty. Alas, the logics have been characterized semantically and no proof systems for them are available. The purpose of this article is to define tree-like proof systems for those logics and to prove the corresponding soundness and completeness theorems.

Motion capture systems for jump analysis


This article presents several methods used in motion capture to measure jumps. The traditional systems to acquire jump information are force plates, but they are very expensive to most people. Amateur sports enthusiasts who want to improve their performance, do not have enough money to spend in professional systems ($+/-20.000$EUR). The price reduction of electronic devices, specifically the inertial measurement units (IMU), are generating new methods of motion capture. In this article we present the state-of the-art motion capture systems for this purpose, from the classical force plates to latest released IMUs. Experiments show that the IMU is equally valid for measuring vertical jump.