what is the meaning of this boolean function in tableau $--->([$country name$]=$ "canada" and $[$year$]=2000)$ or $([$country name$]=$ "china" and $[$year$]=2002)$ or $([$country name$]=$ "china" and $[$year$]=\{$ fixed $[$country name$]$ : min$([$year$])\})$ or $([$country name$]=$ "canada" and $[$year$]=\{$ fixed $[$country name$]$ : max$([$year$])\})$